Re: Watch out Microsoft?
I think this is a pretty obvious thing for Apple to do if/when they convert macOS to ARM. It would give them a big advantage over Android due to the amount of commercial software available on Macs. I think I first posted about this possibility about five years ago.
iOS uses basically the same kernel as macOS, you'd just need to run the OS X GUI as an "app", to interface with a wireless mouse/keyboard and a Lightning to HDMI connected display.
The real market for this though was Microsoft's to own, back when Intel made x86 SoCs. If they hadn't screwed the pooch with Windows Phone, there would probably be tens of millions of people running Windows this way today. With Android (or Mac, if Apple does it) it will remain a niche for people who have very minimal "PC" needs - the type of people who do everything on their phone and use their PC a few times a month. Microsoft could have had a significant usage base in the corporate world, if you could avoid bringing a laptop for business travel that would be huge.