I've seen this argument again, but this is a redefinition of sell vs rent.
Apple sells the device with specific capabilities. You might want it to have others, but that's not the same as renting. If you don't like it, buy something else.
You do get to do "whatever you want" with the device AS provided. You can stomp on it, melt in in a fire, or whatever, and Apple wont ask you for the device back. That's a sale.
"I wanted another version of the device, one that is unlocked, and Apple doesn't sell me one" doesn't mean Apple doesn't sell you what it says on the tin.
They're selling iPhones, locks and all, not generic devices to have different OSes loaded.