Many nordic countries have little to no religious presence, they are in the simplest form a humanist country.
America may not be too far off, but close countries like Canada could be faced with the extinction of organized religions. Interestingly when we consider the mainline denominations in North America we have seen a decline. it's the evangelicals that think they're not going the same way many mainlines have gone.
So what's the solution? Well it's not going to be business as usual that's for sure. Bigger won't be better, and more influence wont come from better integration of church and state.
Faith won't disappear, but how that's expressed will, IMO, look far more organic than the cathedral model we're all used to here.