This has no direct precedents and the case and the lawyers involved need to be chosen carefully, because once the precedent is set it is used by the courts for ruling subsequent cases. You don't want a sloppy lawyer, and the case has to be bullet proof, the judges known in advance (hence why certain districts are chosen for certain types of cases) and so on.
A case of this sort would bring into question so many non-game related things, more related to recent AI copyright and IP theft, that it would far exceed what Valve would be able to bring forward in terms of an argument anyway. Computer game mechanics and game designs are already on thin ice in terms of copyright.
Valve isn't going to fund this, and it is not how legal works.
One case does not a precedent set. Sure one case is a precedent and whichever lawyer it helps will be sure the judge knows about it. However any opposing lawyer will find plenty of details that are "different" and thus the judge should ignore it.
In the US you need to go all the way to the supreme court to get a binding precedent. However the supreme court wants to see a lot of other judge's with lots of different things considered before they set a binding precedent. They are well aware that they don't want to get this wrong and so want to review the thinking of a lot of different judges in lots of different circumstances so they can get the precedent right.
the other way to get a binding precedent is if lots of different cases refer to it and all get the same result and so there is no controversy.
Regardless, I don't see why Valve couldn't fund a lawsuit based on a novel legal theory.
I don't know why people are downvoting me. Folks, Valve aren't going to fund these lawsuits. It's a fantasy.
Edit: I keep trying to reply to you but you keep removing them before I can! It isn't personal in any way. I am simply looking to see what the arguments were and whether it was an already-released game having its assets stolen, vs. a game that is not yet released being knocked off with AI, vs. something else. I wanted to see what the cases actually played out like.
One of the threats that is highlighted in the article posted is that they want to extort games which are not yet released. Which is certainly juicy in its own right.