I think that's a form of hair-splitting. The notion of "adaptation" involves a change to a deliberately different style, location, setting, or whathaveyou. You might as well object that all Bach is an "adaptation" because we do not generally play it on instruments built and tuned as they were in his day. Sure, true, but that's different from, say, a transposition of Bach to an all-electronic ensemble. We would recognize the latter as an 'adaptation' in a way that the conventional presentation is not.

See above about PhDs in this stuff.