My understanding is that the GPL doesn't have fucktons of precedent behind it in court. You bet the house on a big case and lose, the precedent will stick with GPL and may even weaken all copyleft licenses.
Also, it's better to gently apply pressure and set a track record of violators taking corrective measures so when you end up in court one day you've got a list of people and corporate entities which do comply because they believed that the terms were clear enough, which would lend weight to your argument.
Saying this as a GPL hardliner myself.
Most licenses, EULAs, contracts and so on don't have much precedent in court. There's no reason to believe that GPL would fold once subjected to sufficiently crafty lawyers.
AFAIK it has enough precedent (also depending a bit on jurisdiction, but you only need one) but the interpretations of what that/the license should cover differ. Like f e if you wanted to argue driver devs would have to open-source their firmware blobs or their proprietary driver loaded by a kernel shim you will have a tough time and prob lose
It definitely does have precedent in multiple jurisdictions. Heck, SFC just won against Vizio enforcing the GPL's terms in the US, and there have been previous wins in France and Germany.