Yes, I think he doesn't split out simulation world exploration focused play (Traveller, Harn) from challenge-focused Classic play - you could say Nordic Larp is a narrow, extreme subset of world-sim play with a stronger emphasis on deep immersion? I've only ever experienced deep-immersion play with a German GM, which may be significant!
Well I'd say OSR is that, in spirit.
That's why those aspects of OSR that are too into D&D 1e are more epigones of Classic than OSR as new thing.
And of course I think this style was around just bit shorter than classic, it's clear even from OSR/D&D fans that some played games Classic and some OSR, long long time ago.
But remember this article is not just trying to categorize all game styles around, all tables, but more culture. Ergo larger conglomerations, vocal, ones that shaped discourse for decades. They did not have to be most numerous in number of players (note that there is no something like Casual Culture here - though who knows maybe in 20 years we gonna define one based on modern evolution of 5e scene).
Polish scene for instance started with Trad who soon went into war with Nordic Larp, and later when D&D 3.5 appeared in Poland it was scoffed by both as Boardgame, Roll-playing, Wargame and so on. 4e even much more, due to it's videogame like designs.
And then we should also remember that with all those elements: mechanic design, adventure design, worldbuilding, GM's agenda, Player's agenda - all those can easily mix and merge weirdly between cultures.
For instance Vampire I'd say is generally TradGame (skill based mechanics trying to sim abilities of vampire), but how game was marketed it was much more into LARP type of experience, or maybe even protostorygaming. Emotions and deep deep drama were promised, but game itself did little to none to truly enforce it. So to get this emotional immersion and bleed XD players had to go full amateur actors themselves. And TBH Nordic Larp seems to be one style that can easily engulf almost any mechanics and setting, because it's fundament is - that players and GM should act a lot, and their acting abilities be high enough for mutual immersion, and then you can play 1e, Warhammer, Vampire or Blades in the Dark, and put it into Nordic LARP culture.