The funny thing is I'm not sure that science or atheism will ever fully take hold because of what I observe happening in reality. So it's a rather rational, sober reflection on the world. A bit like saying "well somebody has to pump my gas".
The thing is even in the age of technological superiority we all enjoy, I thought as aptly portrayed in Looper, it seems the "haves" and the "have nots" are a human legacy. We may, some of us, call ourselves middle class, but a Global study would tell you even our homeless are way better off than the rest of the world. You've always had something like that, to varying degrees, in society. In fact, arguably now the gap is far wider than ever. You still have people living in 0 AD like conditions, or worse. You definitely have many living in conditions similar to the 1500s. This may just be survival of the fittest exaggerated.
Most of the life expectancy changes deal with average. In other words less overall infant mortality. It's only recently that we've begun to extend humans to what's presumed to be their maximum natural life expectancy (115 years for a man, and about 125 for a woman).
I think for that reason it's always safe to assume 1) they'll always be a need for a subjugated work force and 2) they'll always be a class of undereducated/uneducated in any given society. I think frankly that's inevitable. Even with technology having humans replaced with robots, someone will have to be at the tail end of that money trail.
Politically also, since resources are finite and the cost associated with transporting them you also run into this again.
As for the religious aspect, not only is it appealing to those is desperate circumstances, I think their is some evolutionary advantage to it. Basically, if you can't hack it as a scientist, or your aptitudes don't lie in something that requires atheism or a belief in God, you may develop a God of the Gaps to avoid those questions so you can focus on what you're doing, which could be playing sports, acting, painting, performing surgery. To be skilled at these things doesn't necessarily need atheism, but it does need drive and focus. Something spirituality and God can provide. I think though, like you see in fields like science and medicine, it's harder to maintain that cognitive disonance. However if you didn't have to encounter it everyday, which many, many do not and will not, it's easier to write off and easier to stay in your corner. I'm not sure, sort of widespread brainwashing, and idea most find replusive, you could ever truly get enough perspectives to come together on all that information.