Here's another point: Wagoner got sucked into the status quo thinking at GM, perhaps best espoused by "Engine" Charlie Wilson, who apparently said "for years I thought what was good for the country was good for General Motors and vice versa." Wagoner still appears to have thought that the US government would value GM so highly that it do everything in its power to make sure GM (and by extension, Wagoner) would remain as they had in the past. Now, if a street-fighter like Lee Iacocca had been in charge, he would have forced the UAW to approach congress by threatening to declare bankruptcy, dissolving the union and breaking on pension and bennies obligations. At this point, the dems in Congress would have to counterargue that a few union jobs were worth billions and billions of government subsidies on a continuing basis to keep GM afloat.
Because Wagoner didn't have that kind of brains or moxie, we've got a brand new British Leyland on our hands.
Cultural. I've heard from dealers and one distributor since the early 70’s that GM just doesn't listen. It's our way, or the highway buddy.