I disagree with PoN's characterisation of science above, but agree it's a distraction and want to get back to D&D.
The reason this entire discussion is getting mired in pettifoggery is because A) two different points are argued and B) you are long-winded. As has been pointed out to you, the single culture point is essentially a strawman. The only meaningful question is whether, on average, via inference or the existence of dominant sources, something called 'oldskool play' can be distilled and contrasted with later cultures of gameplay, such as 5e. The fact the 1970-1977 era had a great deal of individual variety is trivial to the central question; can something be distilled from the body of work, collective experience and wafts of airy vapor emitted from the pits of the Temple floor that is MORE TRUE to what Oldschool play would have looked like then random chance, and the answer is OF COURSE because many innovations you see in modern rpg games simply did not exist at the time, which you yourself acknowledge by producing this typology. IS the current conception of the OSR representative of what it was like back then? A scientist should ask compared to what other model?
I'm long-winded because I started off being concise and was grilled for more details, and any time I did not specify something in exhaustive detail, my not doing so was taken as a supposedly fatal flaw in the taxonomy.
I think that your above statement here presumes a number of things that I do not, and disagrees with a number of things that I do hold.
There are a profusion of individual practices in play 1970-1976 that could have become cultures, but most didn't. I don't think they can be reconciled and distilled into a shared core without imposing a Whiggish historical lens of inevitability over it, and I decline to do so.
I've cited four different examples of radically different play, all of which were in circulation, and I don't doubt there were others. There was nothing to normalise across these play types until Gary started writing essays about D&D in the Strategic Review in 1976 (followed shortly by others there and elsewhere), and the publication of Holmes Basic in 1977. So the question squeen and I are going back and forth on is really whether D&D from 1977 onwards has a culture of shared values that stabilises before Call of Cthulhu, Ravenloft, and Dragonlance and all of that turns Trad into a hegemonic force that suppresses (demeans, excludes, etc.) other ways of gaming for nearly two decades.
I don't even disagree that Gygax is trying to _create_ such a culture, but I'm waiting for some evidence that he was successful.
I don't care too much whether the OSR recreates this proposed culture, since I think it's more interesting that they don't. Instead they combine some of its ideas with a bunch of myths to use as a springboard for new stuff. That's why I don't think the contrastive method here is super useful. My goal isn't to say "The OSR is closest to Gygax's vision, unlike those pretentious trad shits".
Lich van Winkle is terribly angry at Gary for having run over his dog and slept with his girlfriend once and since then he's been determined to show us sweaty nerds how terrible we were by having a hobby and liking a game. Instead we should surrender to the fatalistic precepts of his grim and joyless creed, that all opinions are equally valid, that god is dead and that there is no D&D.
Sure, Lich is an elderly liberal and clearly an early exponent of what became trad trying to engage in myth-making about the early days so he can feel good about himself. I am neo-Aristotelian following in the shadow of MacIntyre. My goal is to organise the domains so that the different possibilities of excellence can be cultivated within each one in as straightforwardly as possible. Like all Runequest players, I desire straightforward and distinct cults to suit all desires.