Faster than you'd think.
It's not easy... around 70% of turnaround attempts fail (something like 30% are out of business 5 years later, and 40% are in the same position or worse), but it can happen. The article highlights Fiat, Boeing and HP. All three had different strategies (Fiat negotiated with unions and improved worker relations while cutting costs, Boeing read demand better than Airbus did and came out with a better plane, and HP cut fat, laying off workers and trimming overhead), but all three worked.
Other historical or current examples that spring to my mind: Chrysler, Toys R Us, Kmart, MCI, Nucor, Circuit City, Burger King.
Why do I post this? Not only because I like stocks, but because this should give people a) hope that some of the banks can be rescued, because their problems are balance-sheet related, not brand or operations related, b) hope that GM can be resuscitated with a restructuring, given some of the work they've done recently on reviving a few of their brands, and c) extreme skepticism about government and union involvement in laying strategy. None of the companies I listed above turned around by conceding to the shortsighted interests of unions or bondholders. Unions and bondholders have rights (the latter currently being abridged by the Obama auto plan, in the case of GM, and likely to not hold up in court), but giving them more than the bare minimum you can fight for is not a recipe for a turnaround. This is especially true of the government as a creditor, because the government is not exactly known for its farsighted organizational skills and investing patience.