Thats what I meant. They will find some other part of the stack to lock down to rules lawyer against the openness of whatever the rest of the stack is. You have an open source Linux kernel, you may have an open source chip, so as you said they might cryptographically lock the bootloader. And now Android I believe is trying to make an end run around drivers in the Linux layer too. If thats true then manufacturers will jump to shift drivers into the Apache layer instead of the GPL kernel. ie if they even provide source dumps at all.

edit: It seems I am misinformed about the moving drivers above part. Perhaps I might have confused this from Fuchsia. In any case the main point was that as you yourself gave the example of, they will always find some part of the stack to hide all the real power/real logic into even if the other parts are open.