But I really don't like the fact that they are fully gated devices. Apple has already keep useful, but competitive-to-them, applications off their platform. They've force developers to eliminate user-beneficial changes to their applications. This is not good even for non-technical users but it's much more difficult to quantify.

One real example is that all users would benefit from alternative competitive web browsers on iOS but they can't have it.

You're already seeing it. Most people under 35 have likely spent most of their "computing time" by playing games on game consoles, which are precisely black boxes of consumption. And this is the result: walled gardens.

But that's how every generation since computers existed has mostly viewed them; tinkerers have been a small minority, even if young tinkerers-of-computers were an iconic image associated with the first generation in which that was a possible thing. That wasn't because they were common, but because it amazed (mostly older) people that they existed at all.