I was off the mark; a generation is around 25 years, apparently.

Regardless I think it's a stretch to say that anti-natalism will be at all popular in a hundred years. Maybe I'm being short-sighted, but it's just not an issue any prominent intellectual figures are attempting to tackle.

(I recall Sam Harris getting asked about Benatar's book in a twitter AMA, and his response was "you can't eat ice cream when you don't exist" or something.)