It's definitely easier to have that degree of support when you've got a common architecture now. There has never been a console generation before this where you had literal years of overlap with games releasing on previous and current gen, because it didn't require much extra work to maintain additional versions. They were already doing that with the "Pro" consoles before anyways.

Hell, PS4 players are even still going to get the highly anticipated Shadow of the Erdtree DLC for Elden Ring in a few weeks.