I envision a future where religious theologies are viewed as “self propagating” fiction books. Where the new generations view their ancestors, ourselves, as having a lack of intelligence for getting mentally trapped in a simple story with cyclical logic.
Children will likely use religious theologies on one another as mental pranks, just to see if they are grounded in reality enough to break free of the "I'll be punished by an imaginary something if I stop believing in this fairy-tale."
Just as today, the religious fear god's wrath if they stop believing. They're told they must have blind unquestioning faith in the proposed being who's existence cannot be proven.
We have a few minor variants of mental pranks of this nature already today.
How many times have you heard pranks like
“If you say Bloody Mary 3 times in the mirror...”
“There's a ghost in that house...”
“At X part of the town, when there's a full moon at midnight...”
All of these require the pranked child to blindly believe in the prank, often with untold consequences if the child “wusses out”.
Just as religion requires you to blindly believe in the religion, often with untold consequences if you back out or “lose faith”.
We will view religions and theologies the same way one day, I'm sure of it.
I envision a generation that views those who can get trapped in religion as mentally weak... to be socially isolated from the larger group. Phrases like “Ignore him, he's Stuck in a Book.” or “Wouldn't want you to piss off your imaginary friend.” will likely emerge in whatever slang future generations come to use.
Just as those who cannot see the difference between a movie they recently watched and reality get socially isolated, as too will those who cannot free themselves from the religious dogma that is thrown their way.