It is no more the warband generation.
Nowadays players switch from one game to another in no times.
And a lot of new games have been released recently as well (Elder ring, Total War WH, CK3 Royal Cour,...).
I don't see why TW should be bothered by this high volatily though, they already sold millions of copies. It is not like they are proposing any kind of subscription either.
Those "one day players" will come back once the release is done and will pay for the future "Viking" DLC...
Multiplayer is there and will get in popularity after full release and with custom servers...