Bean counters and out of industry CEOs are sometimes acceptable choices for a successful company with an established management culture. Keep an already well-running ship on course, and nothing more. Do no harm.
But for companies that are FUBAR, like GM has become, you need someone who can tear down the operating structure to the foundations and rebuild it to function properly. That requires knowledge of the nuances of the business model. GM is a manufacturing business. A guy who grew his telecom business by orchestrating mergers with other telecoms doesn't seem to fall into that genre. Unless they're going to merge GM into Ford at some point.
Bear in mind, though, that this was a chairman selection. The board chair is not the same as the president. The latter should be making the day to day decisions that really matter. That selection remains to be made.