You might see a need, but it isn't going to happen, especially in small and medium sized businesses.
Wine and Proton work for many things, but far from everything. Plenty of games don't work well on the Steam Deck.
Ergo, Windows isn't in any near-term danger. As far as Android and iOS being markets, sure. So what? It doesn't threaten Microsoft that there are additional markets.
> Plenty of games don't work well on the Steam Deck
Are you just referring to the games with anti-cheat? If so, I do agree, though I think with the success of the Steam Deck the anti-cheat providers are (or better be if they don't want to get their asses kicked) going to be looking seriously into options.
Outside of anti-cheat, I've yet to find a game that doesn't work on Steam Deck. Even the ones with the worst ratings will usually launch and you can play if you plug in a mouse and keyboard. Obviously not a great experience, but those games would have the exact same problem on any PC, Windows or Linux. It just happens that most Windows PCs have a keyboard and mouse already plugged in.
Well of course a giant company like this is probably not in a near term danger... it isn't impossible though : too big companies can get split by force: look at Standard Oil or Bell.
But longer term nothing is certain : look what happened to IBM or typewriters.
Wine and Proton work for many things, but far from everything. Plenty of games don't work well on the Steam Deck.
Ergo, Windows isn't in any near-term danger. As far as Android and iOS being markets, sure. So what? It doesn't threaten Microsoft that there are additional markets.