Well, choice is about compromise. You have to choose between freedom and convenience, but you can choose. I'm saying that as a person who used 4 linux phones as daily drivers for last 10 years (n900, n9, jolla, xperia with sailfish).
> There are other choices but are they mainstream
Well there are. Maybe they are not mainstream because people value convenience over freedom, which is unfortunate to me, but who am I to dictate them my values.
At least there are always some linux phones to choose from, and hopefully fabless/new open platforms would even increase the amount of such. I mean, 10 years ago it was nokia or nothing, today there are pinephone, fairphone, librem
They could literally put in a button to let you install what you like. In fact they already did this in the past.
There are many open source products that have had huge investments without monetization.
Like what?
I don't think people have much choice these days. If you want a smartphone then you will either get something from Apple or from Android people. There are other choices but are they mainstream? In my local shops I can't see anything else. Android or Apple.
That's why I'm buying PinePhone and going to waste lots of my life to make it fit my needs, but I hope once time is spent I will be happier human being ;)