The year 2020 does worse at 1940 morality than the year 1940 did

From Is There An Illusion Of Moral Decline? by Scott Alexander.  Primarily an essay deconstructing an argument made in another paper.  In the process, though, there is this this insight.

So an alternative explanation for widespread perception of moral decline is that each generation observes moral decline relative to its own standards. If you were born in 1940, you absorbed 1940 morality. The year 2020 does worse at 1940 morality than the year 1940 did, because the year 2020 isn’t trying to achieve 1940 morality, it’s trying to achieve 2020 morality, which is only partly correlated.