OK, we were talking past each other. I was responding to case 1 and 2 in your original
posting, pointing out that bugs, features, and performance issues might cause two independent
works to nevertheless be related -- not in the GPL/copyright derived-works sense, but rather
in the sense that not all possible pairs of versions of the two works could be expected to
work together correctly.
As I said before, I don't have an opinion on the placement of firmware blobs. If I was
attempting to argue for firmware blobs being placed in the kernel tree, I would likely use
analogies with (1) gcc, which is permitted to compile and link proprietary code, and (2) ftp,
where a proprietary client is permitted to interoperate with a GPLed server. But I was not
attempting this argument, rather, I was probing your cases 1 and 2 in your original posting.
Sincerely, Paul E. McKenney (my opinions, not my employer's)