Maybe not. Intel is considering removing rings 1 and 2 for a future 64-bit only x86 architecture, because they "are unused by modern software".
https://www.intel.com/content/www/us/en/developer/articles/t...
And the reason why not is simple. Anything that Microsoft thinks is a good thing to add to the API, they'll add for themselves. When the new API is released, their software is released with it. This gives them a competitive advantage over competitors who have to wait for Microsoft to have the idea that they want, and then scramble to implement it after Microsoft does.
The EU is suspicious of this for the simple reason that Microsoft has a several decade history of doing exactly that. Repeatedly. My favorite example being the release of Windows 95 with Microsoft Word available at the same time, and with WordPerfect unable to run. By the time WordPerfect had figured out how to port their software to Windows 95, they were no longer the market leader.
That is somewhat revisionist history. WordPerfect admitted at the time they saw OS/2 as the future and were focused on that. Only in hindsight did they realize OS/2 was going nowhere (too bad, it was better than 95) and had to rush to get a WordPerfect for 95. Worse for them, they wrote each release of WordPefect in platform specific code (mostly assembly) so it wasn't a case of port to 95 it was a case of start over mostly from scratch.
Yes WordPerfect lost to Word with 95 - but it was bad decisions on WordPerfect's part. They had opportunity to get WordPerfect on 95 much faster. I don't know if it would have been fast enough, but they didn't even try until it was too late.
It was full of ad infested solutions, which would crash your computer from time to time.
Defender at least was reasonably performant and tended to be stable.
You could say that since they had access to kernel source, they were better informed, but I guess if there was an API, the provided documentation would solve the issue (not necessarily, not everyone bothers to read the docs).
But then you get back on how to enforce equal and open access for everyone (the EU did try to make Microsoft open the Word file format, but turned out it was so complicated and documented in legacy code only, that Micorsoft had trouble giving useful docs)
Anyway, as you said, it's complicated...
The ultimate lesson then is to stop using MS stuff.
The fact that Microsoft abandoned it as soon as a regulator pointed out how anti-competitive the design of the API was makes you wonder what Microsoft's true intention was. To me that implies the anti-competitive design was its main feature and to Microsoft it would've been pointless to continue without it.
On Windows.
