Microsoft owns PC, and even Valve has forced to emulate Windows/DirectX to have any games on SteamDeck.
The amount of office worker typing Excel sheets on mobile phones is rather tiny.
If you include the massive mobile gaming market, Windows gaming is an even tinier percentage of the overall market (maybe even <10%).
That would be a first.
What matters is where money is, and how much of those games trace back to Microsoft owned studios.
Good example with mobile games though, as it is a good example of Valve's failure to capitalise on 80% of mobile games being run with OpenGL/Vulkan, on a Linux like platform, and yet they have to translate Win32/DirectX, as means to get games on SteamDeck.
Guesswork is rarely helpful