The problem is now that this exists and is easy to set up, it's easy for the manufacturer to make a device where they're in control of the keys forever instead of the eventual owner gaining control.
You mean... The last decade or so? Pretty much Mobile period sans the Librem 5 and I think maybe one other? Anything with an ARM chip that'll run windows must be secure booted and signed by Microsoft.
Or how about Nvidia(mostly)/AMD(to a lesser degree) video cards, where the entertainment industry increasingly relies on cryptographic attestation to constrain what people can do with hardware they bought? There is no "fully unlocked" buying option, and trying to divest yourself of Nvidia is impossible while being able to use your card to the fullest.
Or John Deere with their crippled hardware as a service model?
I'm all with charging for convenience. That's a value add. I'm not cool with intentional crippling, and extortionate practices whereby the manufacturer maintains ultimate control after first sale either legally or practically through privileged access to signing keys.
Just look at how fast the industry flipped over from dumb TVs to smart TVs, a similarly competitive and low margin market. I haven't been able to find a dumb TV at a big box store in years and the only options left are for commercial signage displays that command a large premium - largely made by the same brands that make the smart TVs.
I have a Pinephone myself but Android and iOS have already sucked all the oxygen out of the room - it's still nowhere near ready to be a daily driver and it's a decade plus late to the party. I got a small open source 3G cell tower for development years before the Pinephone even hit the drawing board.
Absolutely no web presence outside of (essentially) a brochure and email complaint form. I thought about complaining but I really don't care enough.