Yeah, his last handful of movies (everything 2000 onward) were astonishing levels of pure shit to an extent that is hard to comprehend until you see them. I dunno what it is about certain directors and how they lose all their style and touch (example: Dario Argento post mid 90s) in such a spectacular flame-out, but there it is.
Spielberg happened. He never got over the rap that Spielberg ghost directed "Poltergeist", and he couldn't beat that professionally. Spielberg basically used the man as a pawn to get around contract obligations. Apparently he fell hard into drugs and alcohol and never recovered. Spielberg is great at what he does but he's also a spiritual black hole that dessicates people around him.
While I agree re: Poltergeist, Hooper made some great stuff after it. (TCM2, Invaders From Mars, Lifeforce, the wonderful schlock of Spontaneous Combustion) But even his bad, later 90s tv movies were still clearly made with a certain level of production and care.