If the terms were so great and the value to developers so high, it should definitely have been able to succeed in a competitive market, and need not have been forced on people.

I think most of the praise was because before the App Store, you quite literally could not install software on iOS. If the Mac worked the same way, people would absent-mindedly praise Apple for it too.

Because it was better than anything existing at the time (fees in the few existing stores were up to 70%).

That was 18 years ago. The times, they are a-changing