And realistically Microsoft has a very good moment coming up in the next few years to effectively kill Steam: Valve only delivers pre-compiled files and does not have access to source code. Therefore Valve is not only stuck with a “Windows-like environment”, they are also shackled to x86. With Apple’s M-processors reigning supreme in the laptop space with insane values for performance-to-powerdraw (and in turn heat radiation and cooling requirements), the days of x86-by-default laptops are probably numbered and more manufacturers may want to switch to ARM, to avoid unfavorable comparisons to MacBooks. With Windows for ARM Microsoft can finally kill of all traces of Win32 in WinRT, as they tried for years and force everyone to use UWP-apps from the store exclusively on ARM. Apple does leave apps behind, when updating their operating systems on a regular basis, a similar move by Microsoft wouldn’t look totally unreasonable. The switch could even happen gradually, like Apple’s Rosetta translation layer, which runs x86 apps on arm great right now, but I don’t think it will be maintained forever and support for x86 apps on macOS will end one day. Microsoft could do the same for Windows for ARM. If this happens Valve will probably have the opportunity to install games as UWP-apps, but their back catalog of Win32 .exes becomes effectively worthless. But if Win32 .exes run great through some translation layer on linux, valve can continue to sell and support their back catalog on current hardware.