Let's be honest here: A smartphone costs the same to develop, produce and so on, regardless of if you simply buy it or rent it. The companies need their profit, so they will not start renting you a phone when it is more profitable to sell it to you. It should make you suspicious that they want you to rent, because that kind of tells you that they will make more profit from renting than selling. That means that you will pay more for your phone in the long run without owning it.