Corman never got any worse. He stayed the same while the rest of the industry got better.
He used to accidentally produce a few classics amongst the schlock because his outfit saw a lot of real talent passing through it on the way up. That doesn't happen anymore at the rate it used to.
Corman's heyday was also a time when there were more subjects/attitudes that mainstream Hollywood wouldn't touch. There is far less of that now. 40 or 50 years ago he might have been the only outfit in town willing to touch Game of Thrones.
