Why should 3rd parties be allowed to sell unauthorized devices to be connected to the telephone line? Additionally, phones are only monetized through leasing,

Why should 3rd parties be allowed to sell unauthorized devices to be connected to the telephone line? Additionally, phones are only monetized through leasing, and 3rd party phones aren’t leased. How do you expect the 1st party to stay in business? I don’t align with AT&T on a lot of issues, but they should be able to control which phones connect to their network. Don’t like it, don’t use it.