right. courts have a lot of power which they will use if they decide someone is being unreasonable. I'm not making a prediction of what the courts will do. There isn't enough case law to be sure (and nobody really wants to chance it so there probably never will be)
Isn't there any case law for license violations in general? For the purpose of this discussion this is just yet an other license violation, not necessarily tied to the GPL.
You basically say that the court can order the copyright holders to offer an exclusive proprietary license to the violators for a "reasonable" price.