I have never owned an Apple device, but they clearly believe locking them down is part of the appeal of the devices in the first place.
If you want an impartial platform get an android; if you want a curated ecosystem get an apple
Do they believe that? Their behavior and stance could equally be explained by pursuing their economic best-interest
Every big software publisher having its own store implies that our details will be stored in more databases, which increases the risk of hack or leak. The alternative would be to not get apps that we can currently get without risking much. It is hard to see this as a progress.
Apple could do the same thing. They won't because the reason for the walled garden is revenue. The user privacy and security gambit conveniently aligns with generating revenue.
But there are other solutions. The other solution is that people are allowed to do what they want, with phones that they own.
And you don't have to download other app stores, if you don't want to!
Develop applications right on device! My dream.