They still are. Any PS5 will play PS4 games. The PS5 Pro is a mid cycle spec bump that allows some newer games to have slightly better graphics. The games are still hard required to function within the expectations already set for the first PS5 model. I played Ghost of Yotei just fine on a non-Pro, and it targets the newer model.

We're also nearing PS6 time in the next year or two. It's already six years old.