When technology enables massively extended lifespans (sometime from around 2040) religion will have lost its last big sales feature
May I ask why?
How dying at 200 or 2,000 (while keeping each individual's ego intact, if not reinforced by a longer lifespan!) would pose less of a metaphysical or existential problem than dying at 30 or 80? What exactly would that change to my self-understanding and my relationship to the "Other" (what "I" never was, am not and will never be, at least on a purely phenomenal level)? This is precisely what religion has been increasingly about, and religious "answers" to this issue would be even more needed in your hypothesis.