I think you guys are misunderstanding the role of a producer, especially when it comes to independant filmmaking where the director is the money-fronter. Kurtz coincidentally worked with Lucas when the content was good, and McCallum when the content was not as good.

Kurtz' claim of a "mutual parting" is a way of putting it--after he goofed up on Star Wars Lucas gave him a second chance and it almost destroyed him! Lucas is either just too diplomatic to say "i fired his ass" or Kutz actually doesnt realise what he did wrong (which was obviously since he continued the same screw ups he made on the SW films in his post-SW career).