Sure if you owe someone $150,000 and have a net worth of $500,000 they'll take you to court. But over a cell phone, that probably is not going to happen.
Also when the debt is sent to collections the originator only gets about 1/10 the cost.
If you owe money on the phone, it's not your phone. Whoever you got it from should have the ability (technically and legally) to just brick it remotely.
If you have a loan on something, it's not yours. If you stop paying your car payment, they take it away. If you stop paying your mortgage, they kick you out. (And neither of these absolves your financial responsibility). I don't think it's particularly surprising to suggest that if you haven't paid for your phone yet, whoever gave it to you still owns it.
But I never suggested you can't "do with it as you wish" only that bricking the phone was a perfectly reasonable way to ensure that it was paid for in full in the example of someone getting a subsidized phone but wanting to switch carriers a few months in - which should be allowed, provided you pay back the subsidization.
12 states have 'non-recourse' mortgages, where if your mortgage is foreclosed on, the lender has no legal avenue to recover the difference if sale does not recover the principal.
More generally, what provides for recourse isn't the vague idea that 'you're still making payments'. It's a signed contract saying they can. No contract, no recourse. Contract terms for things like cars and homes are heavily regulated. Cell phones are getting there.