I'll quibble on the numbering, and the count, but not the core idea. I don't feel BECMI to Cyclo/Wrath is really a significant change in mechanics, merely in presentation.
Also, Troy Denning's Big Black Box Basic is missing; it's the Cyclo basic. It's the bit that makes Cyclo a different ed, as it's the basic for use with Cyclo.
It's also missing that there are at least 3 hidden subeditions of AD&D 1e, where noteworthy changes were made but not called out. Such as certain printings of AD&D 1E DMG note Dwarven Clerics as NPCs are allowed, while others do not. Similar some other changes that make for significant world building changes.
4E to Essentials really isn't a whole number, either.
3.0 to 3.5? sub-edition.
Oh, and the guy shorts Cook credit for Blue Expert, and by total omission, Troy Denning for the Big Black Basic, which seems to have had multiple different versions, differing in which adventure.
Likewise, AD&D 1E has a major overhaul with the release of Unearthed Arcana, and the changes to maximum levels, multi-classes, Adding the Cavalier class, and changing what class Paladins are a subclass of. The only reason UA isn't a AD&D 1.5 is because they were too cheap to remaster the PHB and do an edition churn.
Oh, and whitebox without sups is a VERY different game from with them.
1.0 OE no supps
1.1 OE with sups 1&2
2.0 Holmes Basic
3.0 AD&D 1E
3.1 AD&D 1E+ Unearthed Arcana
4.0 Moldvay Basic, Cook Expert
4.1 Mentzer Basic/Expert/Companion/Master/Immortal
4.2 BECMI + Gaz
4.3 BECMI + HW
5.0 AD&D 2E
5.1 AD&D 2E+core class splatbooks (due to all the kits)
6.0 Players Option & DM's Option. Oh, and the PO compatible ravenloft...
4.6 Denning Basic & Alston Cyclopedia, Alston Wrath of the Immortals - mostly presentation, but some additional bits. Not enough to separate the Gaz and HWR changes
7.0 D&D 3E
7.1 D&D 3E with first year errata
7.5 D&D 3.5e
8.0 D&D 4e
8.1 D&D 4e Essentials
9.0 D&D Next Playtests - different enough to be a different (and inferior) edition
10.0 D&D 5e Release
10.1 D&D 5e + Tasha's Cauldron
11.0 D&D one playtests
11 major editions, 22 counting major and minor.
My criteria? Major: a glance at the data blocks is sufficient to ID it.
Minor: you can tell in play, but not always from the character sheet. Classes with major operational changes.
And that's ignoring the hybrid wonkinesses of ...
1.1 Empire of the Petal Throne 1e (licensed variant of OE)
Adding the DragonLance Adventures, Greyhawk Adventures, and/or Oriental Adventures are pretty much additional subeditions of AD&D each, let alone combining them...
Similarly the Council of Wyrms, Ravenloft, Dark Sun, SpellJammer, or Birthright settings to 2E - as each changes character gen somewhat and play a good bit. BR and CoW are instantly detectable, Dark Sun has very different PC numbers, and different coins,
So, really, there are 25+ official variants. I don't know the other AD&D 2E settings to judge minor or trivial.
Oh, and BECMI/Hollow world? It makes many more fun oddities that can be "Hey, wait, WTF?"