There is no reason at all that shareholders would fight for GM to stay in the company. Sh*t results for a few fiscal years now, and much longer than what would be allowed from your average CEO. It makes no sense that GM has not been asked to step down.
It also makes no sense that the board wouldn't make similar demands. None. All one can imagine is that they really are there to keep their cushy board positions for as long as they all can, and quite happy to watch Medtronic go down in flames for the privilege.
This is the real concern: the board don't seem to care.