I do not fault GM.
I think the fix was in for GM once the imports came in, took market share, and never stopped.
GM had zero chance to lock the Japanese out of the market... even if GM had done the best possible job, a free market values competition, and more competitors WILL take market share away from you.
Once GM had large, FIXED medical costs and large FIXED pension costs with a shrinking market share (that they could have done more to hold onto, but COULD NOT have prevented) there was no way for them to remain solvent long-term.
GM's probable future insolvency was nearly impossible to prevent.
The only way I can see for GM to continue to producing cars is to go bankrupt, lose its obligations to the unions and retirees, lose its cash, and have the government say that they're allowed to keep their plants and intellectual property. (Chrysler-1984 style.)
Of course, if GM can't make money on a facility, the government should just sell that part off and give the money to GM's creditors in the fashion prescribed by law.
If GM didn't have its existing benefits obligations and has or will have competent management, it has at least a shot at continuing to make cars. Since their bargaining position is basically terrible, the unions WOULD NOT be able to get the kind of sweet deal from GM post-bankruptcy they have now.
This would leave them in the position of having substantial manufacturing assets, lots of brand equity (for some vehicles) and gobs of intellectual property and blueprints.
If they cut their product lines to the top 75% most profitable at their most efficient plants and kept their corporate management/overhead lean, they could certainly make money. Perhaps that 75% should be 50% or 25%, but you get the idea.
GM *can* make money, they just need to cut overhead and shrink their model line-up to the stuff they make good money on.