I'm surprised Google still didn't use something like Wine (+dxvk) to bring more games to Stadia sooner, while the library of native Linux/Vulkan games is gradually growing (which isn't going to be super fast process). Is there a reason for that?
You can't just "bring games to Stadia". First off you need the approval from the devs. We've seen Blizzard and Bethesda pulling out their games from GeForce Now. Next, the way Stadia is designed, it requires actual porting to use its APIs, which is a non-trivial amount of work required from the devs.
You can argue if it's the right design or not, but as it is, it takes time and effort to move games to Stadia, so it's not as trivial as just running them on Wine.
Adding support for Stadia SDK (for remote input and video streaming and such) is not as difficult, as writing a Vulkan renderer in the first place, for a game that doesn't have it. Incentives are measured against the difficulty of the whole work.
I'm sure, using Wine+dxvk as a first step for existing games is a lot easier than writing native Vulkan renderer. In this sense, Google can actually provide one level of incentives for native games (higher one), and another for Wine use case.
I.e. developers can first release it in Wine (phase 1), and then make a native version for example (phase 2) to improve performance.
What Google could do, is to provide integration of their SDK with Wine for phase 1 above.
