I would not call being dependent on Windows games a solution.

The file format and APIs used are irrelevant as long as the games work. The games work and that is all that matter.

Not when it is a castle on Microsoft's kingdom.

Sorry but that makes no sense, there is nothing in "Microsoft's kingdom" here, Wine -as you certainly know- is independent. The most Microsoft can do is change the API in backwards incompatible ways - but that'd affect Windows too, so there is little incentive to do that (and attempts such as Metro/UWP/etc to change the core ways of working with Windows didn't prove popular with most gamedevs).

And even if Microsoft does that, it isn't any different than the 2394923th time a library breaks its API on Linux - Linux as an operating system isn't some monolithic project, it is a combination of hundreds of separate projects that for the most part work together like -sometimes misshapen- bricks on a wall. Wine/Proton is just another of those bricks (and history has shown that it tends to be among the more stable ones).