This makes it possible for the OS companies to bilk the entire industry while they protect their ecosystem with an infinitely deep moat.

There's a spectrum here. On one end, we have completely a completely open OS. Less knowledgable people can certainly be harmed. On the other, the OS is a protected fiefdom. An entire industry is protected and taxed, and the execution model held hostage. You can't run or distribute software freely.

There's good reason Microsoft lost their case. The requirements for openness are better for competition and innovation, even if it sometimes hurts the little guy.

A better, targeted solution for this exact case might be regulation requiring that OEMs offer a zero-bloat option to consumers. They could add a price markup to make back their margin. (Hardware, other than luxury hardware, can have razor thin margins.) Zero regulation (maintaining the status quo) isn't really the end of the world, either.

All giants should have weak points. Microsoft, Google, Apple, etc. If they don't, we get trampled.