Then why didn't he walk away? He ended up coming back and taking the same deal they were offering (him and everyone else). I get he has his talk show which, I would presume in his mind, is actually worthwhile compared to doing the Simpsons, so if he just wants to keep busy and have a positive impact, he'd have quit the Simpsons and just done his show. For the record, at 20 episodes, you're talking about the difference between 6 and 9 million (he accepted the $300k an episode, down from $450k). Unless you're a billionaire, you don't walk away from $6M/year for a few weeks worth of voice work.