Sure, though they may chose to wipe iOS from your device if you unlock it. Then you are free to build your own os and execute root level code if you wish.
Okay, so you want to live in a world where you buy a car and the manufacturer will wipe the engine firmware or lock the vehicle if you change oil without their permission? Thats already happening to farming equipment.
You will love in a world where you own nothing, and have less control over your life than a medieval surf - all devices are becoming 'smart', frok door locks to toasters
South Korea is already doing significant laws that are at least related to this conversation.
I expect more countries to pass similar laws soon.