It sounds like the parent poster's relations have freely chosen to delegate their technology management to him or her, and in turn the poster is comfortable delegating that to Apple and their walled garden. If Apple is selling safety, security, and control, and people are buying it, what's the issue?
Potentially the issue is a lack of competition in the market when there are too few options; but it sounds like you're saying that no one should prefer a walled garden option at all.
We have plenty of precedent from microsoft being forced to allow software before. Apple and friends have lobbied (bribed) heavily for antitrust and antimonopoly to no longer have teeth. If it were 30 years ago apple would have been put through the meat grinder.
If we need the legal right then we'll legislate it.
The idea of loving apples walled garden comes from a position of extreme privledge. You have to have lots of money to afford apples ecosystem. The hard reality is just like automobiles an iphone has become a societal requirement to participate in the common market.
You can't install 3rd party apps by default in android, you have to turn it on.