This kind of behavior, as questionable as it is, would be totally fine if Apple didn't also employ a variety of technical measures to ensure that it's impossibl

This kind of behavior, as questionable as it is, would be totally fine if Apple didn't also employ a variety of technical measures to ensure that it's impossible to install software from outside their store. Consider the Mac App Store: there are lots of restrictions, but no one really cares, because you can just...not use it.