It's not really fair to talk about SteamOS 2 and compare it to 3. The original concept tried console gaming and failed, because it was banking on devs porting games to native Linux. With Proton, things are a very different beast.

Windows is unlikely to be unthroned from gaming king, but Linux has grown quarter over quarter and Valve very clearly is expanding into multiple partners with Lenovo's new SteamOS handheld.

Having a competitor in this space will hopefully get Microsoft to stop being complacent.