As far back as the 80’s there were means of distributing software without paying a retailer a commission on every sale. Shareware [1] was one such model. The software was distributed by users copying it from floppy to floppy, handing it out at user group meetings, conferences, even on the school playground. It was later included in large CD-ROM collections packaged with computer magazines.

The point is that you could distribute your software any way you wanted to without permission or license fees paid to the maker of the computer or its operating system.

[1] https://en.wikipedia.org/wiki/Shareware

The ship has already sailed on that long ago.

If there's a new store on the iPhone, virtually no one will use it.

The default is good enough, it's already installed on ~1Bn devices, and most of those devices use it somewhat regularly already.

During most of the time since Windows exists, the majority of its users have not paid for Windows separately, but as a part of the purchase price of a new computer.

Android could also be paid as a part of the purchase price of a smartphone and maybe it already is, but of course a one-time payment would be much less profitable for Google than a continuous stream of revenue from the apps.

majority of the world never paid a single cent for windows

I think you meant ads instead of apps.