I didn't assert that having one "app store" violates basic notions of ownership and property rights. I don't even agree with the anti-trust basis of the majority of the Epic vs Apple lawsuit. I think the anti-trust angle is juvenile and ridiculous. I do however think courts should induce legislation on right-to-modify and the definitively decide whether or not Apple is legally allowed to place a surcharge on transactions that occur after a user "buys" (they call it "licensing") an app.
There is no guarantee a jailbroken iPhone has to work. There is no mandate that Apple must make a phone jail-breakable. There is no legislation dictating that they cannot render a phone inoperable if a user tries to jailbreak it. And it is not even clear just how OK it is to void a warranty if a phone is jailbroken. The most recent version of iOS cannot currently be jailbroken. This entire notion of jailbreaking phones is a gentlemen's agreement between the consumer and Apple (and a host of manufacturers of Android's phones). Your details on cars are great- didn't know most of that. It's nice that there is active legislation on the books that governs what can and cannot be done.
Ditto for the ability to sideload *unsigned* apps onto an iPhone. If it works, it's because Apple has chosen to allow it- not because they have to by law.
So I actually completely agree that it is within Apple's purview to do this: "aggressively retain control of how all users of their device browsed and paid for new functionality". I think the walled garden approach more broadly has serious benefits to security and UX. I don't think we should be able to compel Apple or Google to offer a store, either. I like most of your points and keep in mind that you set up some straw-men. It's totally OK for Apple to compel people to pay for apps through their store on their device. Where things get fuzzy are:
* Can Apple prevent devices from being jailbroken if they so choose to?
* Can Apple (and Google) render a device inoperable if it is jailbroken? Want phone calls, no-no to jailbreak?
* Can Apple disallow the sideloading of apps?
* Can Apple (and Google) through the legal morass that is a EULA compel developers to only use a specific method of in-app purchases, while collecting a fee on them? Again, this broad power is generally reserved for the government in the USA, EU, UK. The user in general owns their phone and is not leasing it from a 3rd party or the manufacturer. This sort of top-level, general surcharge invoked as a financial transaction is also ludicrously regulated within the banking industry (pretty sure you knew that already). It's regulated up the wazoo.
The ignorant will go: "those questions are all answered! it's not illegal!"
No. First, just because Apple and Google have been doing something for a while, doesn't make it legal. Second, just because individual states have not pre-empted any applicable laws, does not mean it will remain legal. I believe it is time we received distinct answers and case precedent on these questions in the USA. I don't want unspoken, incidental rules. The only issue that actually has active legislation right now is "right to repair", and that is only in less than half the states. In the rest of them Apple can compel you to only have iPhones repaired at their officially branded or sanctioned stores. Flagrant violation of ownership refers to stuff like that- if everyone who bought a new car had to go to the same dealer or dealerships to have any repairs done without violating their warranty, they'd riot! They'd go batshit crazy. Phones have come so far because for the longest time they were a novelty, a pocket Facebook or Twitter for most users. Now they're not quite so. Everything else is basically "not illegal" and existing through gentlemen's agreements. I don't like this, I really don't think you should either, or anyone technical. Even if leaning towards a hyper-capitalist view of technology in industry, it's not really ideal for Apple and Google to just do whatever the hell they want because our politicians are too lazy or incompetent to provide answers.