If you're talking pre-1890 or so, the people would still have had more cousins than the latest generations. The population was still going up at that time, just slowly.
When looking at countries like Japan you're talking about rapid depopulation after the older generations die. Even in the US population growth is mostly caused by migrants within 2 generations.
Industrial farming is a relatively new invention. Yet it didn't immediately deliver equal rights, contraception, or education for women. Doubtful we'll roll back any of those, even if the future of antibiotics may be in doubt.
And before industrialization population gains from agriculture were limited; albeit significantly more than the hunter-gatherers. Yet it was the that lifestyle which dominated most of hominids' existence. So I'd argue population is reaching a peak, and that's not a bad thing.
When looking at countries like Japan you're talking about rapid depopulation after the older generations die. Even in the US population growth is mostly caused by migrants within 2 generations.