Anyway, let's analyze the lethargic pre-WotC pace of D&D revisions:
1974: OD&D
1977: Holmes
1979: AD&D (last core rulebook published)
1981: Moldvay
1983: BECMI
1989: AD&D2
1991: Rules Cyclopedia
1995: AD&D2 Revised
If we are going to include different lines of product, and all smaller products...There were quite a few forgotten for 3e/3.5 which would be
D20 Modern
D&D Basic 3.5 (Black Dragon)
D&D Basic 3.5 (Blue Dragon)
Star Wars D20
all of those are just as much D20 as B/X BECMI were D&D.
Unearthed Arcana was also for 3.5
AKA...there's a difference between revision, and differing lines. BX was separated from AD&D early on...AD&D to D&D is what we are talking about, not the separate Basic D&D line which finally got to be the BECMI line.
Also of note
That version was killed off, died over 10 years ago...
If one views it as a continuation of OD&D...then that was revised far more overall...and as I said...it's dead Jim...it was also a separate line. If you are including that you may as well include ALL D20 variations for the D20 line.
The actual real line would be
AD&D 1e
AD&D 2e
D&D 3e
I might accept the 2e revision...but there was probably just as big a difference between the original 3e core rulebook printing...and the final 3e (prior to 3.5) erratta...in which case as the errata was easily online you'd have to add
3e Errata version
3.5 Errata version
Moreover if we include optional books which could have significant impact on the game (such as Unearthed Arcana 1e) we would then have to include the 2e player options (which many call 2.5), but with 3e that would include All the Class books (with as many classes and feats I'd say they were as significant as some of the 2.5 Options books), and then with 3.5 the Complete Books version, Players Handbook II, Unearthed Arcana...and lest we forget...the BIG one...book of Nine Swords...and though not really popular...possibly Incarnum.
That's attributing a LOT of revisions to things that are either separate lines using the same core idea (which is the same as your B/X BECMI versions to AD&D idea) or saying optional books outside of core rules are revisions...which is equally ridiculous.
Overall such inclusions of separate lines or changes small enough to be errata is ridiculous. Which is why when people talk about revisions...or throw fits it's NOT 3.5 with class books vs. D20 Modern...or D20 Modern with D20 Future...
It's 3.X or 3.5 vs. 4e...or 2e vs. 3e...etc.
PS: As I said...if D&D ceases to be published in a few years...most likely after 5e...you can't say this came out of nowhere...that no one expected it or warned you...or even pointed out the problems. Of course seeing some of the blind responses here I expect a LOT of whining from people who can't believe that bad marketing skills would lead to the demise of WotC or D&D. On the otherhand, maybe I'm the one in the wrong...but we won't really know for a few years yet...