Even among the religious people I know, the younger ones are really clueless about basic bible stories, and too many think the Ten Commandments are originally Christian beliefs.

I'd say the rise in atheism and non-theist/non-religious Americans would be that we've fully transitioned into a post-modern society in which the old standards are being revised.

As more and more people leave religion all that is left is the nut jobs.

Religion has been declining since the rise of humanism and science 200-300 years ago. Human rights was never really a thing until then, and it emerged separate from religion. As to science, ask a believer who they are looking to for COVID relief, Anthony Fauci or the Pope? If their child is in an accident, would they take her to the hospital, or the church?

Maybe they’re looking at what the religious leaders are saying and realising it has no bearing on. Christianity. I do hope so. The first step in realising the whole lot is garbage hopefully?

Not a source I’d usually quote, but an interesting article from fox news on the matter:

[foxnews.com]

No affiliation does not mean no religion, there is a lot of mumble jaumble new age woo in a big part of those folks.
Plus, people are not being "converted" you will have to wait for the religious people to die and hope they can't make other folks religious in the process.
The trend is also that religion increase importance as people age...