> And then there was Windows RT (not to be confused with WinRT, because Microsoft product naming!). Aka the Windows-on-ARM that ditched decades of backwards compatibility because Sinofsky decided that rebooting the ecosystem is the only way to compete with iPad or whatever.

It's important to remember the specific reasons why Windows RT 8 chose to not support third-party desktop apps. The most important aspect of "iPad compete" that we wanted on Windows for ARM was not "all app UXes look and work well on touchscreen tablets" but "you can't ship malware, not even by rebuilding your x86 malware from source." Thus, every 3rd party app on Windows RT would have to live in the AppContainer sandbox that UWP apps are in by default, and the requirement that you ship through the artist formerly known as the Windows Store would be a second line of defense against malicious apps. And with the forced-enabled Secure Boot, subverting the user-mode controls by secretly installing a bootkit would be hard even with physical access to the PC.

Even within the Microsoft world only, Windows Phone 7 had proven the success of this approach of locked-down apps only available through an app store that checked apps on submission and afterward for security. It was not unreasonable to think that similar lessons might also benefit users of "big" Windows, which is why Windows 10 and 11 have the opt-out "S mode" which defaults to the Windows RT restrictions.

I do wish though that Windows 8 had learned different lessons from WP7 (about which more in another point).