...a religion, which strives for political power and have always done so.
A religion that does not gain political power often finds itself at the mercy of one that has gained power.

Hence there has been a wittling away of virtually all faiths that do not have political clout. Even internal sects will get removed if they fall prey to a stronger ones political moves (Templars).

In the end the more political faiths will increase in frequency while those less fit will die out.