I would say that carrier locked phones are undeniably anti-consumer though, and they are banned in many jurisdictions. Their sole purpose is to add friction and give the customer less choice, and due to 'collusion' between the few carriers that exist, impossible to avoid, even if you did choose to purchase the phone outright; it's practically the definition of anti-consumer. The phone purchase should be a separate contract, with a defined monthly payment against the retail price of the phone. Offering this is a profitable enterprise for BestBuy etc. on other electronics, so why not phones? The user should be free to switch carriers with little friction, to maintain as competitive a market as possible in a market that is a natural monopoly.
It reminds me a lot of the equipment monopoly in the Bell System until the early '80s.