You need already a significant "PC market share" to get video games, but you will never get that "PC market share" because you don't have video games.
But in the first place, you will really not get that "PC market share" because people uses what is installed by default on the PC they buy. So you will need mass default installation of elf/linux on PC first of all. Everything else is pointless for "PC market share", only hardcore (omega hardcore) regulation can do anything here.
Regulation for video games: forced support of a set of as simple as possible exe file format and OS interfaces, very stable in time, namely not msft ones which are disgusting and grotesquely complex and massive (but msft would be forced to support them). And if regulation happens, it will happen most likely for other more important things than video games (for instance, critical online services of administrations or utilities).
In the end, we are reasonably left only with the good will of game devs.
And I think proton is not helping here, to say the least.