This fear is unfounded. It isn't the proliferation of technology that is making people dumber; it's the American cultural deemphasis of education, entirely independent of technology.
https://en.m.wikipedia.org/wiki/Demographics_of_atheism#:~:t....
You can even publicly state same in most places on Earth today and not be beaten or killed.
The situation improves even faster with the mass education that the internet allows for.
I could make further points that new faiths have become more entrenched, such as nationalism and political partisanship to name just two. Or even beliefs like free markets being some unquestionable good, or maybe that technological progress is inexorable. That these kind of tribal splits are increasing, betray this notion that we are becoming more rational as a species. I’d posit that even if we did cast off the shackles of religion, we’d simply find new kinds of faith to replace them.