Yeah, as we've seen time and time again, how you ask the questions can affect the result of your survey too.
Anyway, I think I've mentioned this before, this forgetting about God trend as we achieve better standard of living is even recorded in the bible. People are naturally like that. When we are doing well, we don't need God anymore. Most so called 'believers' don't really love God. They only love God's blessings. Only when time gets tough and after we tried out all options and exhausted..., then perhaps we'll remember that perhaps God can help? Of course, there are also those with hardened hearts probably will only remember to blame God for the bad things that's happening to them... basically believing that there's no God when time's good... and believing God is an asshole when time gets rough.
Anywho, if Christianity is really just the world's most successful ponzi scheme, then I have no doubt it'll eventually come crumbling down just like other mythologies and fall into irrelevance. Nothing bogus can last forever. However, 'religion' itself probably won't ever go away though. Just as the survey showed, people giving up on Jesus don't all become materialistic atheists. There are still a LOT of 'spiritual folks' who can end up believing in whatever else that suits them. A lot of them are probably just sick of organized religion, but far from atheists.
If one day we can get rid of prostitution, drugs, war, etc, then perhaps religion will also eventually go. Now, I'm not implying it's religion that caused all those other things, it's just that those things are part of our human condition. Paradoxically, yes, we're a bunch of fucked up people, and at the same time, wonderful too. At least according to my belief, Jesus saw our redeeming value that's why he came to save us out of our fucked-up-ness. Otherwise, God could've just wiped us all out and cut us off like cancerous tumor. If I were God, yeah, I'd probably give up on humanity long ago. But good thing I'm not God... and I'm still in awe of how amazing this God is.