Why Do Monotheists Outnumber Us?

Over the years, one question has come up repeatedly. It may have been in conversation with other Heathens or maybe while talking to an interested outsider. In the big picture, it is a really good question. If our Gods are the real Gods, then why are there so many monotheists?
To answer this question, you have to approach from several directions at once. It is made more difficult by the fact that the cultural framing of the question is often influenced by those same monotheistic religions. That doesn't mean there isn't an answer, so here we go.
First, a little history…
We normally think of the ancient Egyptians as being polytheistic, and that is how they were for the most part. At one point, a pharaoh named Akhenaten decided that they should be monotheistic. He told them to throw out all of the other gods and just worship one, represented as the sun. He was reasonably successful while alive, but the whole thing was dumped as soon as he died. It is important to note that the time of Akhenaten is close to the time when the people who would be Israelites were said to have been in Egypt.
About that time, or a few centuries later, Persian Zoroaster started his own monotheistic religion. Zoroaster opposed polytheism after conversation with a "bright being". He also taught the idea of a Heaven and Hell and that people were made up of body and soul that would be rejoined after a judgment day. These concepts would later be borrowed into the Hebrew religion. Zoroastrians still keep a lit fire in their homes to signify their connection to that bright being.
The stories of the Hebrews are better known in the western world since they are shared with Christianity. It is important to note that when the Hebrew god shows up, he shows up as fire, such as a burning bush. His servants, the angels, also show up associated with fire, such as swinging fiery swords.
What's the deal?
There are two important notes to these monotheistic religions. First, they are only kind of monotheistic. They have picked one deity and decided that he or she is the only one who should be revered as the Only One. Then, to deal with all the other entities, the worshipers labeled them as non-deity, supernatural helpers or enemies. Essentially, they've kept all their other gods, but have just relabeled them.
The second thing of note is fire. Akhenaten looks to the sun itself as representative of his god. Zoroaster talks to his bright being and his followers treat it as fire. When Moses talks to his god, he talks to a burning bush. The angels of that god go around swinging fiery swords.
Guess who else is fond of fiery swords: the fire ettins.
In Asatru, we know that humans exist as allies of the Gods to help maintain the dynamic balance between order and chaos because that balance is the only place life can exist. There are entities that would prefer to tip the balance one way or the other to suit their character better. The ice giants, also called frost ettins, are patient and slow and are willing to weight for entropy to do its thing. The fire ettins, with their leader Surt, are more active.
The point of the monotheistic religions is to pull people away from the wholesome work of the Gods and to accelerate chaos and destruction. The fire ettins are the ones behind it. They've been working on humans to do this for quite a while.
How does that explain the spread of monotheism?
The attempt with Akhenaten didn't get very far, but was probably educational. With Zoroaster, concepts such as duality, monotheism, and the body/soul took root. The idea of just a body and soul is easier for people to grasp than the more complex Nine Part Person of Asatru, or even the Five Part Person of the Egyptians.
The Hebrews adopted their god through their covenant, which is basically a contract. They agreed to worship only him and he would take care of them as they moved around. According to their histories, they moved a few places, smiting the locals and taking over. Anytime things didn't work out, they reaffirmed their commitment to the agreement and things got better.
There was only one problem with the Hebrew religion, from the ettin point of view. Hebrews were a tribe and the covenant only applied to them. The ettins needed far more humans involved in their chaos. This brings us to Christianity.
A big difference between the Hebrews and the Christians is that you have to be born a Hebrew, but anyone can be converted to Christianity. (NOTE: I've heard there are exceptions to being born Hebrew to join up, but in general, they believe they are supposed to be a specific people.) In fact, the evangelistic component of Christianity insists that every Christian person try to convert every non-Christian they encounter.
The spread of Christianity certainly introduced some chaos. It moved quickly across Europe and parts of Africa. There were two ways it spread: violent conversion and peaceful conversion. The violent conversion is well documented, and if you are Asatru you have probably heard the stories. The peaceful conversion is the reason that the religion has staying power.
In Asatru, you are required to make an effort to the best of your ability. We also recognize that everyone has different levels of skill and talent, so some people will be better at things than others. This tends to develop into a social hierarchy. Those who are not at the top of the hierarchy may not be happy about it. If they are Asatru and want to be better, they will continue trying because that effort is the real key.
In Christianity, however, everyone is equal in the eyes of their god. Moreover, if they behave themselves, they believe they will find paradise when they die and then be bodily resurrected at a future time when the world has been purified. At that time, they will be blessed and happy and not have to toil. They will live forever in joy.
For some people, Christianity seems like a much better deal. Imagine that you can just pray while sitting there and believe that everything will be better when you are dead. Compare that with Asatru where sitting around is bad as betraying your Kindred. For so many, the apparent ease is too much to pass up. It also helps that they are told from an early age that not belonging to that religion means an eternal punishment at the hands of the enemy of their god who helps their god by punishing the enemies of their god.
What about Islam?
Christianity spread relatively quickly through Europe by following the structure of the old Roman Empire. Early footholds with the Franks and the Saxons in Britain held cement the religion in place. After Norway fell to the Christians, the holdouts were surrounded. There were still Heathens around, otherwise there wouldn't have been leaders like Widukind in the Saxon Wars and there wouldn't have been the stories recorded in Iceland.
The ettins created their monotheistic religion to bring about chaos. As Christianity became established, the amount of chaos dwindled. Something else was needed. This is where Islam comes in. Again, the ettins picked a prophet from among the humans and impressed him with their magics. Soon, there was another monotheistic religion attempting to take over the world.
Since all three of the Hebrew religions considered Israel to be sacred, they all claimed it for their own. In not time, the crusades were in full swing. The European Christians actually sent children on the long pilgrimage to fight. You will note that these wars are still going on today in various forms.
Like Christianity, Islam spread through both violent and non-violent means. When non-violent, they could often gain converts by simply not being Christian. There are tales in the United States where African-Americans have converted to Islam just because they see Christianity as the racist religion of white slavers. European colonization set up similar scenarios in other parts of the world. Islam promises the same sense of value in the eyes of their deity that Christianity promises, but can paint Christianity as a white, elitist, European or American religion.
Back to why they outnumber us
Asatru expects everybody to be able to defend themselves to the best of their ability. We also know that the ability varies significantly from person to person. When we initiate war, though, we tend to send the people who specialize in war, only sending everyone else when really necessary. There's no need to pull farmers away from food production just for a bit of a fight.
Christians and Muslims have a different philosophy. Just like Africanized honey bees, these people will swarm with little provocation. Their leaders can get them riled up to war, regardless of the long-term damage it does to their food production. Refer again to the Children's Crusade.
Most of them are not swarming most of the time. Instead, they are going through their lives believing that they will go to paradise just for believing in their deity. They also constantly fear eternal punishment if they stray from their assigned beliefs. Just as the path to Helheim is wide and gentle (and a little slippery), it is just easier for most people to follow those religions.
What do we do about it?
It would nice if all of humanity understood the Gods and that we are their allies. It would be even better if everybody could act like it. If nothing else, it would be nice to go to the Three Milkings Holiday Sale at the store.
For now, it is unlikely that we will do many conversions. There is nothing in Asatru that matches the evangelism in Christianity. You are welcome to (peacefully) convert people if you are so inclined. It is more likely, though, that we will have to focus on behavior.
As allies of the Gods, it is our job to maintain a wholesome bit of growth and life in the Middle World. We do that through honesty and diligent effort. There is nothing there about actually having faith, though I recommend it. That means that even people who believe in monotheism can participate.
In our dealings with others, we are to encourage that wholesome work. We try to avoid damaging nature to the point where things won't grow. We avoid being unnecessarily cruel or violent. We save deception for our enemies, and only then when needed because we know dishonesty leans us the wrong way. Not only are we supposed to do wholesome things, but we should encourage others as well.
Someday, humanity may return to the Gods. I hope it will be before the Last Great Battle, but it is probably not to be. After the Battle, when the remaining Gods are picking up the pieces, and the remaining humans climb from their shelters, it will be a Heathen world once more. Let's not be in a hurry for that to happen though.