The biggest threat to Windows is Steam

[JEMC]

I'd argue that the biggest threat to Windows is Microsoft. They are the ones that have been messing with Windows, making each new version less user friendly and bringing more and more troubles and compatibility issues. What's happening now with the latest Win11 24H2 release is a clear example of that. That is what's giving Valve is a chance to disrupt the market.

Also, with a bit of tinkering and a careful pick of hardware, you can already build yourself a SteamOS desktop to play games without too many problems and still have a nearly fully functional OS to do regular stuff other than gaming.

LTT posted a video showing it a couple days ago:

https://www.youtube.com/watch?v=tdR-bxvQKN8