Page Six talked to Isaac Hayes about his decision to leave South Park. And while he admits he wasn’t happy with the infamous Scientology episode, he claims his real reasons for leaving were money and respect. He apparently wasn’t paid as much as he thought he deserved, and the show’s creators weren’t nice enough to him.
Because, you know, his career of bit parts and guest roles between singing the theme song from Shaft and becoming Chef was really keeping him in demand. I’m sure he turned down a lot of roles to do that voice work.