Paulo Branco sure has this reputation but you pay the crew or you don't… I'm sure Gilliam didn't part ways with his producer on a whim, the money must not have come on time, that's all.

Yeah Gilliam had a version with Duvall as Quixote and Ewan McGregor for the role of Toby (taken by O'Connell now) in 2010 or something but it never went into production really.

I felt that Gilliam was constantly trying to save the film from its incoherent script…

Actually he's been officially totally sober for 10 years now.