There are multiplayer games from 30 years ago that still have 30 people who play on the first Friday night of each month, and they will put that in their calendar and keep the game alive.
The idea that multiplayer games need huge communities of players otherwise they are "dead" is what is killing multiplayer games.
I haven't seen this youtuber's videos before. Do they normally drop 40 minutes of spoilers for a game that came out just 6 months ago? I thought this was going to be a review and it turned into a walkthrough less than 10 minutes in.