I think many companies were on the "verge" of bankruptcy at one time or another in their history, but putting out good products along with other things helped them to get out of the hole. Without good products that people actually buy there is no chance they would ever bounce back regardless. This is what they lack right now and it seems like the trend will continue for another 2-3 years at least.
I don’t think the few new Cadillac or Buick models will save GM, as they are not volume sellers, but Chevy and even Saturn could. However, there is not much in store for them for the next 2 years other than a new Equinox, which it better be good or else....