SoD has a separate lobby on the HD mod, that's where that 12 comes from. Both lobbies are pirate friendly by the way.
I checked GameRanger, and there were 5 lobbies with 1-2 players each. As far as I know, it only allows vanilla.
Checked Twitch, 90% of the streams were on HotA.
There's also Steam version, which I don't have and don't plan on having, so no idea how many are on that. But, it's the Steam version, so yeah.
And there's probably some people in third world countries like Brazil, who play it locally with irl friends.
Seems consistent on many platforms, overwhelming majority does appear to play HotA.
Maybe you know some other way to play the game, which has thousands of players playing vanilla. Please tell me if I missed anything crucial, a secret club of some sorts.
Though to me it seems clear you're talking out of your ass, and have no experience playing with others. Which is fine, if you enjoy SoD for its single-player experience, that's great.
But for multiplayer, I value opinion of thousands other people who do play multiplayer, over a single autistic sperg.