That's a matter of convention. When I was growing up in the Midwest? Every gamer I knew used "OD&D" to refer to both the LBB/white box edition and the later BXCM/red box and RC/black box editions. I'm used to the older "lumping" rather than the newer "splitting" that occurred on Dragonsfoot post-200X where we now have to refer to every single little sub-printing by an author name or an alphabet soup acronym.
I was around on message boards at the turn of the millennium too, on the Mystara Message Board (at WotC) and the Mystara Mailing List. And you're right that we (in the BECMI/Mystara community) referred to BECMI as "OD&D". That usually stood for "Old D&D" rather than "Original D&D." There was also Richard Tongue's ODDities magazine, which was BECMI oriented. So I understand what you're saying.
At time (1998-1999), 3e hadn't come out, and my generation (who grew up 1980s) in the Mystara/BECMI community context, was not very aware of the 1970s Original D&D, and so we just used "OD&D" in contrast to AD&D (2e).
But with the advent of D&D history sites, we've all become aware of the difference between the manila OD&D booklets and the various iterations of Basic D&D, beginning with Holmes.
The naming convention has changed. We are no longer in the year 1999 on Dragonsfoot. And it is clearer to distinguish OD&D (Original) vs. BD&D. Even the editors of that time (e.g. Moldvay, see below) used this terminology, contrasting "Original" vs. "Basic."
Yes, ruleswise, the various editions of BD&D gradually blended from OD&D to RC D&D, but even Holmes BD&D was a clear shift, with a new moniker "Basic." The manila pamphlets were really from another era.
We know at least that TSR internally treated it all as one single game line, "the D&D game" (otherwise, notes
like this one would make no sense);
Huh? It makes total sense. The image you shared affirms what I'm saying. The editor there distinguishes the "Original Set" from the "Basic Set" as two different editions. In other words, Original D&D vs. Basic D&D.
Yes, they were both branded "D&D". Yes, BD&D is a later edition of OD&D, both branded "D&D."
In contrast to "AD&D." Because "D&D" and "AD&D" were legally kept distinct due to Arneson royalty calculations.
Similarly, AD&D1e and AD&D2e were both branded "AD&D". They were both "internally treated as one single game line." But 1e and 2e have their own tags on ENWorld.
By your logic, D&D 3e, 4e, and 5e should be subsumed in "OD&D" since they're just branded "D&D" as well. Even from a legal perspective, 3e was only allowed to be branded as "D&D" (instead of "AD&D") because WotC successfully offered to buy out Arneson's stake in the "D&D" brand when WotC purchased TSR. Are they are all the same edition since they're all legally the same "D&D" brand / game / lineage?
and that this general attitude is right there in
the text of the booklets in places. I vote for keeping the broad OD&D tag we have now.
What general attitude? That Original D&D and Basic D&D were both editions of the D&D brand? In contrast to the AD&D brand? True.
Yet Moldvay distinguishes "original" D&D from "Basic" D&D in the Foreword to Moldvay Basic: (boldface added)
"The original D&D rules are a classic. [...] When I revised the rules I tried to maintain the spirit of the earlier rules. [...] In the half-dozen years since the original rules were published, TSR staff has answered thousands of rules questions. [etc.]" --p.B2
That's a matter of convention. When I was growing up in the Midwest? Every gamer I knew used "OD&D" to refer to both the LBB/white box edition and the later BXCM/red box and RC/black box editions. I'm used to the older "lumping" rather than the newer "splitting" that occurred on Dragonsfoot post-200X where we now have to refer to every single little sub-printing by an author name or an alphabet soup acronym.
Um yeah, that may've been the convention in the late 1970s / early 1980s, in that place. (Once you reach the mid-1980s, hardly anyone had heard of the manila booklets.)
Like I said above, I agree that prior to the release of 3e in the year 2000, the main contrast was "Old D&D" vs. "AD&D." Conventions change.