On phones, things have gotten much worse. Although you can flash a relatively open ROM in case of Android, good luck controlling what the baseband does behind the scenes.

And if we talk about cars and other devices like smart watches, there's often zero openness.

I actually have a lot of sympathy with that one, because radio transmission is one of those areas where one idiot who thinks he's clever and should have total control of his device can literally disrupt entire networks for everyone else over a wide area, with the obvious serious consequences. Modern wireless communications systems rely much more than most people realise on conventions and standards and everything playing nice, so regulating such that only licensed practitioners are authorised to make parts that transmit within prescribed specifications is not an absurd idea.

Of course, that doesn't mean a closed part of the system like radio control should have any access to any other part of the system. It ought to be essentially a firewalled client of the more open parts of the system. And if it's going to be regulated and controlled then the people licensed to develop those components should be required to have them only perform the defined function according to standardised specs, without anything else piggybacking on top.

Right now we don't know whether for example it's even powered when your phone is on airplane mode and collecting data.

I'll just leave this here.