Earlier quoted context omitted.
Agreed. I actually think it might be too late at this point since it takes so long to turn the aircraft carrier. Microsoft can't realistically deprecate/remove Win32, so all they could do is entice with new APIs. That will work for some games, but especially with the frameworks in place, they'll have to be really good to get people to abandon Steam Deck compatibility to use them.
They already control enough studios, PC and XBox market. SteckDeck compatibility relies on "emulating" Windows ecosystem. Remember DR-DOS, OS/2 and EEE PC.
Valve is neither tiny, nor does seem to be under the thrall of hubris. Also Microsoft seems complacent so far, though that might change.