> Valve basically failed to provide the business value for those studios.

For a studio selling their games via Steam, there is no benefit in making a Linux build.

Their clients still need Steam to run it, and there's no practical different between Steam creating a container with a dedicate Linux userspace or with a dedicated Proton setup.

The audience that REALLY cares whether the game is Linux-native or not is likely the audience that wouldn't want to use Steam.