As for Toyota-style management? It's difficult to do with strong, uncooperative unions. Want to replace 100 workers by robots? Not happening. Want to give workers decision making power, tempered by accountability for their decisions? The union demands more money for the decisions, and thinks that "accountability" means "talk to the steward."
There is a reason Toyota builds factories in Kentucky instead of Detroit.
http://www.nytimes.com/2007/09/04/business/04uaw.html?_r=1...
I'm not saying GM made no mistakes, but unions did play a huge role.