The classic period of Meddle/ Dark Side/ WYWH/ Animals/ The Wall, was just that. They couldn't maintain it once Rog fully took over and gave Rick the arse, and they couldn't recapture it when Dave took the reins. But how many bands could? None of the Beatles ever made anything on their own that could eclipse their work together.
The post-Wall stuff isn't bad - it's just not as good as some of the best albums ever made.