I think of religion's relationship to humanity, in terms of the OSI model for networking. By this analogy, you might consider religion to be questions concerning the Application layer, the layer that 99% of people actively care about. All the rest of the human OSI stack below the surface is transparent to us, e.g. 99% of people don't care about bits and bytes in the same way they don't know the ordering of the bases on their DNA.

A data packet from a streaming movie is meaningless when you look at the 1's and 0's going over a wire. You have to step back and impose a framework of understanding, protocols and specifications that exist outside of the computer itself, before you can watch the movie. An atheist transistor could never be given "proof" that a movie exists using a sequence of bits. The concept of "movie" exists outside of the world of binary. Religion is to humanity what protocols and specifications are to a stream of binary data. This is frustrating to the types who consider themselves to be rational and fact based, because by definition it cannot be proven within the system. The difficulty for the hard nosed atheist is that all of the most important human questions, including their desire to convert us all to atheists, cannot be accounted for in their reductionist framework. This is usually dealt with by simply ignoring the dissonance.

What you call "religiosity" I would call fundamentalism, and it is a natural human phenomenon which will manifest no matter what the professed religion or non religion of a person.

Human concern about the ultimate questions of life will not go away no matter what religion we ascribe to ourselves. The good thing about formal religion like Christianity, is that it incorporates thousands of years of debates by some of the best minds about these issues. Throwing it away and making these questions ad-hoc or even worse, subconscious, is asking for the serious consequences you alluded to in your comment.