There’s nothing really “wrong” with GM’s books. It is their business plan.
They knew they were bleeding cash since about 1999 to 2000. Starting in 2002, they starting buying down UAW contracts, etc. They’ve gotten a new pay scale for new employees, etc.
Still, they were losing money on most cars they shipped - but they would lose money more slowly than if they had the level of sales they’re seeing now. Much of their expense load is fixed, and they can’t shed it when they’re not selling cars. If they could sell enough cars, they could make the cash they have last much longer, but with auto sales plummeting as they have this year, the true scale and inflexibility of their expense load comes into view.
You bet their business model is screwed up. What's worse, they all know it. So why the HECK don't they declare Chapter 11 and reorganize? That is literally the only course of action that will save the companies. I can see the union not wanting it. But management?? They'd rather let Congress nationalize their companies?? The only reason I can see the union and the managements colluding against their companies' best interests is because they don't dare let anyone get a look at the books.