The one thing I don't understand about Apple's stance: why don't they let a device owner sideload things SAFELY on their own device? Something like the Apple Developer Account, but for free, and I get a certificate that works on a single device - my own - ONLY.

I still need to understand software development, and probably to own a Mac just to sign things and to upload them to my phone. They could even provide something like a web interface to perform the signing and/or notarization, so people cannot invent magical desktop software to make signing easier for random users.

This would effectively defeat the "walled garden" objection, but make things hard enough that 99.99% of iphone users wouldn't bother.

With the notarization system (is it applied to ios apps as well, I suppose, not just to Mac apps?) they could even prevent piracy.