Buy more so that their economics and capabilities can be improved so they can sell better for cheaper.

That’s how economics work, right? Someone will have to buy phones enough that it becomes financially viable to pursue the needed improvement (including eg.: getting better open hardware or even getting patents on already existing hardware released).

Manufacturers aren’t going to ditch Google. Play Store and Google certification are too valuable for them.

If legislation is made such that eg.: in the EU phones can not be registered in the cellular network unless they are open to both normal installation of apps (sIdElOaDiNg) and being able to fully install or remove Google Services, then Google will have to deal with who would want to work and pay to get a certification that effectively blocks you from selling and operating in one or more continents.

And such legislation would be not without precedent: open phones and custom ROMs are already suffering from it.

What’s good for the goose is good for the gander.

Someone will have to cave in if we want to break this stupid proprietary duopoly.

Honestly that’s not a chicken-and-egg problem. Only one party of the two in this example has the power to create or change apps, whereas people in this example, even if they would use Linux, they effectively are prevented from.

The “someone” who has to cave in is obvious.