True, but from my point of view, OD&D is extremely different from what we now think of as D&D, and AD&D was where they actually got big, went beyond pamphlets with passable art, and started getting the religious activists riled up.
Of course, this is speaking from my point of view as a dabbler in everything rock from Chuck Berry to Alice in Chains, so I don't expect my opinion to be shared.
Oh, I neither fault you for your POV or reasons. I was just putting us all back on the metal page.

If you wanted to go over arching musical influence and what they would represent I would go with:
OD&D - Gregorian plainchant (the real monophonic stuff not the updated modern versions)
1e - early Baroque - charming and sweet but not quite there
2e - Smooth Jazz - all the intricacies of regular Jazz without the dirty stuff
3e - Hard Rock - widely accepted by a wide audience but a little over the top
3.5 - Progressive Metal - less accepted by the masses because it gets complicated
4e - The Wiggles....or Pop music - mass produced to pull in those that otherwise wouldn't listen and in smaller bite sized doses.
(I'm a former professional musician and music producer, metal is my favorite but hardly my only dalliance - producers need to keep their ear on the ground at all times.

)
My real feelings about D&D and metal are that they have very little in common outside of the combat. I use classical soundtracks and historical music to back up my games, modern stuff reminds me of why 80s fantasy movies are less appealing than the modern stuff. (i.e. Ladyhawke was a great movie but the soundtrack, though written and performed by Alan Parsons, who is an incredible musician and composer, just makes me bristle with uuggghh)