IIRC Postgres has supported predicate push down on trivial views like this for over a decade now, and possibly even more complex views these days (I haven't kept up with the latest greatest changes).
Postgres can do it, you're correct, but in my experience it rarely happens with any view that's even slightly non-trivial even on recent versions of Postgres. Most views with a join break predicate pushdown. It greatly reduces the usecases of views in practice.
