This should apply not only to phones. Every device with CPU and programmable memory should allow user to reprogram it. However, the user may waive this right for purpose of theft protection.

Agreed. And it does not mean that they should open source everything.

If I buy a connected fridge, they should give me a technical way to flash my own OS on it. Maybe I will lose most functionality by doing that, and maybe it will be a lot of work for me to get the OS working properly with the fridge. But it should be possible.