Right now it’s still birth rate, to be clear. Life expectancy as gone up by mere years over the decades, while births per adult woman is still double digit in a few select countries.
Biology is exploding right now, though, and I fully expect aging to settle down suddenly. I’ll have to look up what Logan’s Run is.
Edit: 30 is definitely too low for a maximum age, lol. People commonly work into their 60s. I expect that decline in age will slow down as well, so that helps offset things, and then if there’s still a population crunch geezers like me should start doing “lotteries”. Maybe literal Russian roulette, for the style factor.