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.