God is like the Forth Road Bridge.
Everytime the painters get to one end, they go back to the other side and start again.
God changes. God used to be anamistic in conception. Still is to some, but it is rare now.
Huge polytheistic pantheons rose and fell. Only one is still going really, and Hinduism isn't really polytheistic as all gods are part of God and we are part of God and are made of god too, if you look into it.
Dozens of monotheistic beliefs have come and gone. There's maybe three left that qualify for the term 'world religion'.
And idtheistic beliefs, where the indivdual is seen as the heart of the divine experience, well, there's one big one.
Men merely remake god in a suitable form for their needs. Ug made up the lightning god. Mohammed made up Allah. The OT YHWH was probably cooked up after the return from exile. Joe Smith made up the Mormon god. Ron Hubbard made up Scientology. Russel lmade up Jehovah.
Those gods that are left today are not immutable. Just as Christianity was shorn of its ore offensive characteristics and doctrines over time, so shall Islam. How many Hindus REALLY believe the world is on the back of an elephant?
This means religion will survive an awful long time, as religion is just as subject to the laws of "natural selection" as giraffes. Giraffes that are easy to 'catch' or religions that are easy to 'disprove', don't have many 'descendants'.
I would say that more religions will become fluffy, meangingless but satisfying life accessories, based on an ancient tradition but shorn of all impact in the daily life of those who claim they are members beyond the 'feel good' factor. They will do this because this will be the only form of religion that can survive the modern world.