Why didn't Apple ever use this argument to get rid of Cydia? In fact, it was Cydia's creator that sued Apple for blocking alternative App Stores. Cydia didn't lose on the grounds of API ownership.Just because the APIs are accessible on a personal device doesn’t mean you have the legal right to use them for commercial purposes. Access is not the same as a license. You might be able to technically use those APIs by jailbreaking a phone, but that doesn’t grant you the legal right to distribute apps that use them, especially through unauthorized channels. The fact that something is possible doesn’t mean it’s permitted under the law or Apple’s terms of service.
Cydia distributed apps, for money, that use those APIs, if I, as an end consumer, have not purchased a legal copy of the iOS software how were they able sell those apps for money?
So you admit you don't want consumers to own anything anymore, happy to know you are cheering for the wonderful dystopian future in which corporations run the world...Think of iOS like a rental car. You’re allowed to drive it because you’ve agreed to the rental company's terms. The rental company's terms prohibit you using it as an Uber. You might figure out there is no technical prohibition from using it as an Uber, but that doesn’t mean you’re legally allowed to start using the car as an Uber without permission from the rental company.