The Sub model.
WoW is still the dominant leader of the MMORPG market even though it has been in decline for 10 years now.
Comparing WoW vs any other MMORPG whatever seems a bit silly, not only are those MMORPG in their prime in their life while WoW is in its worst state possible.
WoW is also not F2P or B2P like those others MMORPG.
Imagine if WoW Went F2P, my bet is that WoW could easily pop over 10-20 million active users once the payment barrier is gone.
I doubt any MMORPG reaches 25% of that.
Don't you think WoW always has a back up plan? F2P. (They can make money anyhow through cash shop like any other game)