I think you're limiting the use to "pirated app stores" yourself. There are other apps on those app stores, ones that Apple wouldn't approve, but are still usef

I think you're limiting the use to "pirated app stores" yourself. There are other apps on those app stores, ones that Apple wouldn't approve, but are still useful. Taking away the question of whether Apple has the right to determine what is moral or ethical (I argue that they don't), I agree with the op in that the primary reason is to maintain the walled garden.