From Economist.com, is an article about GM's mounting troubles.
Exactly how and why things have gone so wrong is a matter of debate. Certainly, the situation was dire 13 years ago when a newly energised GM board flexed its muscle. They turned to Jack Smith, who in turn signed on Mr Wagoner, then barely 40, as one of his top lieutenants. The new management closed plants, cut the workforce, sold lacklustre component operations and seemingly restored much of the company's former lustre. By the boom years of the mid-1990s, GM was again rolling up record profits.
Yet, despite a few exceptional years, sales continued to decline. Critics, such as Dan Gorrell of Strategic Visions, a Californian consulting firm, say GM concentrated more on finance and marketing than designing and making cars. Indeed, after the company's annual meeting, Mr Wagoner conceded: "If we had a chance to rerun the last five years, we problemably would have done a little more thinking about making sure that each product was distinctive and had a chance to be successful."
Looking at the history of GM brings to mind the old saying that "the biggest barrier to change is success." Dominating the market for so long problemably built a corporate culture with a monster ego, and when the market changed the company didn't because the ego got in the way.