Actually, they can pull the dealership from a dealer if they don't make quality standards. One Caddy dealership closed up near where I used to live (Crea Caddy - maybe Mike knows these people). The new dealer was required to increase the size of the showroom within a certain amount of time.
If a McDonald's gets a lot of complaints about a particular independent francise, they will investigate. If there are problems with the way the restaurant is run (other than the restaurant sells lots of unhealthful food), McDonalds will either pull the francise or take over the restaurant if the problems aren't fixed. Likewise, if a dealer refuses to repair cars with complicated problems (I know of one dealer who was known to try to get complicated problems sent to another dealer) or gives a really poor costumer service experience, the car makers should be able to step in.
My dad used to sell and repair Kohler, Tecomsah and B&S engines. If he didn't meet the quality standards (mostly for training), he would not have been a dealer for them.
I would be surprised to learn that if a dealer doesn't do an adeqaute job, that the maker can't pull the francise. I think the Japanese excercise these rights more often than the big 3.
Jeff