Timely question.
Steam is facing a class action suit from developers because of its dominance (75% US, 80% EU, 50% global) in PC games both PC only or with console equivalents. (Since they don't do Plays Anywhere one would expect a slight tilt towards MS from folks interested in cloud gaming. So far it hasn't factored in.)
In the US MS probably moves maybe 15% of PC games, both XBOX-equivalent and PC only, maybe less, even though they only charge 12% transaction fees instead of the "industry standard" 30%. Tough row to hoe.
Which probably explains Spencer's comments about bringing Steam and other stores to XBOX, which obviously hints that the NextXbox will be PC compatible, though I seriously doubt it will be a rebadged gaming PC as some suggest. That wouldn't align with Spencer's other comments about $1000 consoles.
Walled garden pricing models are getting serious scrutiny these days and the some of the dominant players aren't going to enjoy where it is heading. Google and Apple, for starters. AZURE and cloud computing are getting questioned, most commonly in Europe where underinvestment has left them at the mercy of the big US players.
Sony is facing a similar lawsuit in the UK which they will likely lose because, unlike XBOX they don't allow other retailers to sell digital codes. Nintendo might be next.
The other whipping boy, Amazon, has been repeatedly sued over the Kindle ebook store but they are golden because the DOJ antitrust suit proved Agency (and its 30% cut) was literally forced on them by the big publishers. So unlike the console vendors they get walled garden commissions while making a reasonable profit on hardware. Some folks just don't think things through.
That last applies to the nostalgia for Windows phone.
There simply isn't enough profit in the category for anybody else.
Theoretically, MS could do an XBOX phone as their entry into mobile gaming but neither the tech nor the market exists for it, not at a profitable price. Consider that foldable phones still only hold 1.6 of the market despite moving 18M units. Does anybody think MS could move that many high end phones off Windows compatibility? The Duo was aimed at their bread and butter corporate productivity market and failed to make a dent. They looked at a foldable screen version and walked away instead.
Phones are commodities. (Unless you spend a half billion a year in commercials pretending yours are somehow magical.)
Commodities need massive volumes and small margins.
Finally, Samsung is already there and they are relatively good partners to MS. So why mess that up for at best minimal gains?
In the MS corporate mindset ventures need a path to billions in profits. And there simply isn't one for phones. It's not a nascent category like AI or AR wearables.
Too late the hero.