The management at the big three auto companies hasn't been very brilliant or innovative, but I bet they've done just about as well as the management teams at comparably sized companies. Firing all of them would probably just cause a lot of chaos and waste decades of learning and experience.
This financial problems they are facing have more to do with the credit crisis than making the wrong kind of cars. There is this insinuation in that media that if Ford had just made more eco-friendly cars then everything would be ok. There is still plenty of demand for american cars and trucks (especially in the american south). It seems like they just need some time and money to re-negotiate things with the unions and this can be worked out.