Not credible, because if even a few people stay away from futuristic, all consuming super-porn, and can convince their kids to do the same, then those people will come to predominate, and the super-porn becomes irrelevant. There are already people who would consciously eschew any form of entertainment that would prevent reproduction - the Amish would ban it within their communities for sure.
On the other hand, if just one person with control of an adequate supply of nuclear weapons (or other super-weapons, possibly including ones that haven't been imagined yet) decides to wipe out humanity, he stands a good chance of succeeding. This seems much more plausible than mass suicide via entertainment.
But is it likely that there would be enough people (with never a dip large enough to spell disaster) who live on the razor thin edge of rejecting the technology that leads to dead ends hundreds of years later but still push forward the technology necessary for advancement? Is there a stable organization that can do this?
I agree that violent distruction is more likely now, but I think that that is probably an easier problem to solve than this one.
On the other hand, if just one person with control of an adequate supply of nuclear weapons (or other super-weapons, possibly including ones that haven't been imagined yet) decides to wipe out humanity, he stands a good chance of succeeding. This seems much more plausible than mass suicide via entertainment.