This discussion is definitely about Apple's monopoly on Ios app distribution. If Apple were to let others distribute apps on the platform, people wouldn't complain as much about their broken store. They'd just use the store that they liked better.
That is not what the parent said. If there were more stores, then there would be more consumer options to choose a more trustworthy store from (like F-droid).
Of course, that wouldn't be good for Apple: Apple would inevitably have to throw out some of the legit apps in the course of QA and weather more criticism; Apple would lose that revenue and their vig; and Apple would no longer have as many apps in the app store.
Like Amazon, Apple has demonstrated that they prefer that some of their customers get fleeced, as long as they get their cut.
"1 million apps and untold billions in revenue, but only 2% of the top apps are scammy... you can figure out which ones, because we didn't bother.."