I guess I had forgotten about Proton, or maybe never really knew how it worked, but hey, that’s cool. According to this page, there are over 14k Steam games that already work on Linux through Proton, which is a pretty huge starting library if they launch a cloud gaming solution.
Maybe that’ll be the difference maker, but again, the tech part is hard, but the fact that some publishers aren’t super keen about cloud gaming in general is another hurdle.