You seem to be completely forgetting all the other PCs and home computers of their time like the C64 or the Amiga. Without Microsoft opening the market for clones the IBM PC might have remained an overpriced office machine and some other company would have created the most popular computer system.

In any case, none of these(not IBM, not Apple, not Commodore etc.) restricted what software you could run on your computer.

The PC started its life as a hobby platform. And there were attempts to challenge the open model - the game consoles for example required devs to license their SDKs and often controllers publishing / retail distribution.

But no one seriously succeeded with a closed PC experience because no one could (or wanted to) do it all - be a fully integrated retail ecosystem - at the time when facing consumers. The internet was arguably a prerequisite for this: all software was sold in physical boxes and unlike game software , the hobby experience meant there was just too much available that was cheap/free/shareware. (My favorite was the assembly hex codes published in magazines like Ahoy! That you’d type in).

Plus, the security of a curated store was on few minds until the late 90s with the internet. Viruses and Trojans existed but they were spread through physical media.

also, Microsoft already was getting its tax from users in the form of Windows licensing, which eventually was deemed anticompetitive due to their exclusivity arrangements.

The closest to a curated ecosystem started with Qlink, CompuServe, AOL and other online services.

Not forgotten, I was an Amiga owner myself ;) But somehow these machines feel like belonging to another universe today. Commodore management would have ruined the company either way, this didn't require any help from the PC. Atari would probably have focused on the games console business.

Anyway, it's fun to speculate about alternative futures :)

IBM did try to put the toothpaste back in the tube with PS/2 and OS/2 and especially with microchannel. The price points on those things were hard for most people to stomach. That reverse engineering white room case changed the landscape. Everything was bundled and IBM sliced it as fine as they could. I was looking to get a TCP stack for OS/2 at one point they quoted me something like 20k for a single seat licence as you needed the whole stack to make it work right. It was clear they wanted the business market and nothing else, with negotiated contracts all around. The hobby market had to go make their own. IBM had its own walled garden before that case. They milked it for all it was good for too.