It is very much still a thing and the contracts still exist in some form, specifically phone financing and locking. If you finance a cellphone from Tmobile, it will be locked to Tmobile until you’ve paid for the phone in full, which is usually over two years of payments. This is why carriers offer deals on phones purchased through them, and have those upgrade-every-year type plans. The contract has just switched from the phone service, to the phone itself. This is also why if you walk into any carrier’s store, they’ll try and convince you to trade in your perfectly good paid-for device for the next years model with a decent trade in value, but only if you finance the new phone.

Not like they used to, mostly. They just replaced "contract" with "equipment payment plan". Because $50/mo for 24 months is easier for a consumer to swallow than a lump payment of $1200, especially when the carrier is giving you a $10 or $20 (or more) "discount" on the phone.

But as long as the EPP is active, the phone is locked to that carrier. And I think that's fair. No different than the bank holding the title while you finance a car.

The thing is that the plans that have these equipment deals are significantly more expensive than others. Namely big name plans like TMo or Verizon, compared to MVNO plans like Mint or Visible. So you end up paying more for the plan because you get "a deal" on your phone (but still end up ultimately paying more).