Secure boot prohibits custom ROMs on most android devices

If custom ROMs will be more popular, it probably will push some vendors to unlock their devices. In the end, I don't think most of them really care.

Well you misunderstand enshittification. It will never get better again. Both Google and Apple have enshittified their phones. You can verify this on the App Store, on the Play Store, both of which have now more than 50% of search result screen space dedicated to ads, more when it comes to scams [1]. AND you can verify this in the financial statements of Apple and Google, where you see what we've always seen in Google: steadily increasing at a fixed rate profits from ads on the play store in Google's case, and steadily increasing at a fixed rate profits from "Services", which is App Store ads.

In Apple's case this has been the only Apple business to grow at all in several of the recent years. In fact there's quite a few Apple businesses that look like they are "revenue neutral", most famously iPads. Google is better, but not by much. Cloud is growing fast ("but why?" is a question that's unanswered. I mean, "because of AI", of course, but ... seriously?)

So not only are they enshittified, and you see them getting worse and worse over time, but the financial statements show: if you're expecting this to get any better either in the Apple or Google case, you're insane. Because clearly ads for scams are worth it for advertisers, and most other types of ads are not worth it. The situation evolves more and more towards the cable channel situation of 20 years back.

You could also reverse the view. The simple question: "are people willing to compromise on hardware quality to get less ads?" has a very clear NO answer. "Are governments/institutions that are totally dependent on these systems willing to pay to either improve phones or make an alternative available?", again has boatloads of evidence that the answer is NO, in all caps.

[1] Search for "credit card" or "lose weight" and judge for yourself. Top results are promoting Apple or Google themselves, everything else are ads, and very bad deals that trivially will neither accomplish the promised financial independence nor weight loss. Or should I put it like this: the credit card deals advertised are so bad they might achieve weight loss. By the way ads designed to mislead, which the top ads for either search obviously are, are what both Google and Apple promised time and again never to do.