"The big great H" has lots of players because they follow a "play to win" approach, which increases your victory chances greatly if you have no life and play all day. They also use recreated 1.8 PvP, which, it saddens me to say it, instantly makes it more popular. They also got a bit lucky.
However, all the big servers are slowly losing players. I know 1 small public server which has an average of 2 players on at the same time, but has been there for years now. Those small ones attract experienced players, so they don't lose them. The big ones are full of people who try something once, enjoy it, and leave (perfectly fine in my opinion, just please don't stack mages in TD please).
The Minecraft Java edition is dying in it's entirety, slowly. But once all the first-impressions amateurs will be gone, only the experienced players will be left to enjoy the game, and the player counts will stop dropping.
So it's not really "OMG IT'S DYING WHAT HAVE WE DONE", it's the natural flow of things. When the initial hype decreases, only true diehard fans are left. That's a good thing, and we should focus on that part of the community more rather than just try to create hype. (This sort of behavior creates games with lots of features but with extreme unbalance).
