Even McDonald's doesn't "get that right over all uses of their name" - there are plenty of shops in Scotland called McDonalds. (In particular, there is a Hallmark-like shop in Glasgow that has the same name as, and is on the same street as, a McDonalds hamburgers).
In Scotland, I can see that being a difficult case for McDonald's to win. But then in the U.S., they win a case against a guy trying to market "MacDimSum", as they claim consumers would be confused that its a McDonald's product. They won that case, so food products cannot have the prefix Mc or Mac. Trademark can sometimes grant vast powers to famous brands.
