I could come up with a thousand reasons as to why this would never happen. Hell, I could even argue that the whole Steam Deck's existence comes from a series of decisions that Valve made out of hatred for Microsoft. So, yeah, it's not happening.

Still though, as a thought experiment, imagining a world where tomorrow, Steam is owned by Microsoft, it's... interesting, to say the least. In the most horrifying way possible, but interesting nonetheless. Quite frankly, I can't imagine anything worse happening for video games. Like to me, this is what a video game apocalypse sounds like.