Say for example there are five Chevy dealerships in the greater Omaha area. If General Motors were allowed to own one itself it could give itself discounts internally such that it could undersell the other dealers and put them out of business. Once the competition was gone it could then raise prices harming consumers. Competition is good for consumers and the laws in question are aimed at protecting consumers.
Yes I know they are also competing with other brands, but some people are brand loyal enough that they would not switch to Ford or Chrysler.
So there needs to be competition between sellers of a single brand, just because some people are so brand-loyal that they would refuse to switch brands to avoid being 'taken to the cleaners?' I'm not sure I agree with this sentiment.
You're also ignoring that the brand (e.g. Chevy) is selling to all of the dealerships. If they raise the price, the dealerships all have to pay if they want the car/truck/etc. Do the dealerships really have that much bargaining power?
Or General Motors gives internal discounts, that kills off the middlemen ("Chevy dealerships"), competition from other brands keeps the prices low. Competition is essential here, you can't just ignore it and state brand loyality.
In this case, the laws that keep dealerships alive are hurting you as a customer; the many testaments of bad experiences with deceiptful salesmen are evidence of that.
Yes I know they are also competing with other brands, but some people are brand loyal enough that they would not switch to Ford or Chrysler.