Android was sold as being "open" and at first it mostly was, so the people who wanted that got an Android device and everything else disappeared. Then Google closed Android over time, at first in subtle ways that weren't immediately obvious and now they're just telling everyone to DIAF. But by then the alternatives were gone.
I mean it seems like your argument is "nobody wants this thing that people keep getting mad that nobody offers". Obviously people want it; otherwise who are all of these people?
There are something like 50 million people in the world whose occupation is software developer. Hundreds of millions, maybe billions, who are some other kind of engineer or scientist or teacher or just curious enough to want to learn things or stubborn enough to not want someone else taking away their choices. Every kid should have a device that lets them experiment rather than one that locks in them in a cage -- it's not like they're doing banking or dealing with national secrets to begin with.
I disagree. There’s nowhere near a billion who give a crap, if there were that many it would be a market that is served and could be highly profitable.
As it is there have always been phones that are open to greater or lesser extent and they have always been market failures, even among geeks.
Nobody cared, so they went away.