When will atheism replace religion is a little like taking some gold and asking how to turn it into lead.
The idea that religion is a salve has been around forever, or so it seems to me, Marx wasnt the first to liken it to opium, this was a positive association which is something most people dont realise (he meant painkiller and the second part of the quote is "the heart of a heartless world").
I dont believe that at all, religion isnt and shouldnt be purely and merely about feeling good, being comfortable and finding happiness, and it shouldnt be a compensation when those things are wanting or abscent either. I've no doubt for a lot of people that's all it is, its a byproduct, I'd suggest of the consumer culture which sells the ideas of ease, effortless living, no need to concentrate, no need to contemplate, no need to wonder, no need to reflect and wonder.
The greatest criticisms of an affluent atheism I can think of is in Aldous Huxley's Brave New World.