So you are arguing that it is impossible for a driver to rely on a feature that is present
only in specific versions of the firmware? Or that it is impossible that a driver might need
a workaround for a bug that is present only in specific versions of the firmware?
Or are we talking past each other here?
Please keep in mind that I am questioning the OP's assertion that there are only two possible
reasons why firmware and driver might be version-dependent. As noted in my earlier comment, I
officially have no opinion on whether or not firmware blobs must be GPLed.
Sincerely, Paul E. McKenney (my opinions, not my employer's)