T-Mobile, AT&T oppose unlocking rule, claim locked phones are good for users

T-Mobile's filing is shorter than the article: https://www.fcc.gov/ecfs/document/1017178290200/1

> T-Mobile estimates that its prepaid customers, for example, would see subsidies reduced by 40% to 70% for both its lower and higher-end devices, such as the Moto G, Samsung A15, and iPhone 12.

This is such a confusing line, you're in control of that. Also if that were true this would be great for you. Don't you want to be making more money? But in practice can you not just enforce this by contract? You must make a 12 month commitment to T-Mobile to qualify for discounted phones.

In the pre-paid market niche, you have people who really struggle to put together the money for an iPhone 12 all in one go, and T-Mobile has essentially worked to create a razors/blade model with some obfuscation. It's possible that disaggregating phone plans from installment pricing would benefit consumers in the long run, but let's not act like everybody would be prepared to transition to that world immediately. (I don't think T-Mobile is exactly concerned for their customers, but this subsidy regime exists for a reason.)

That actually makes some sense and (I assume) you can let the service lapse and keep the phone if you don't have the money right now?

It seems in both cases T-Mobile is making a bet that you'll continue to use their service in one form or another. Is there a reason if it was unlocked you would immediately switch?