I think the best hope for GM lies abroad, perhaps in China or some other rapidly developing country. In their home market, they fucked too many customers, with their short sighted business plan, which was essentially to build pretty junk with proprietary systems and parts, advertise like hell, then make the real profits on expensive parts and repairs, and financing. It will be a long slow road back for them in the U.S. Market, not to mention that folks out of work seldom buy new cars.
In the end, what capitalists hate most came and bit them in the ass, competition.
That problem was once easily solved. Just by up all the street car systems and replace with GM built buses. This time, it won't be that easy. Toyota, Nissan, BMW, and Mercedes all have plants in the U.S. and employ thousands of U.S. Citizens.