I don't know if this is a relevant data point, but I was raised in an atheist communist family, and I still like the idea that people could live forever (or at least much longer than today) and I think the world could be significantly improved.

It seems to me one doesn't need a religious background for this, only to overcome some learned helplessness and status-quo fatalism. Okay, the religion (and also communism) already provide you a story of a radical change in the future, so they kinda open the door... but I think that living in the 20th/21st century and watching the world around you change dramatically should allow one to extrapolate even if they wouldn't hear such ideas before.