Let's be honest, ALL online only games die off a bit with time. No online game maintains all its player base from the beginning. You need to take into account casual players and players that dislike a game and jump ship.
Also, you will find some modes empty because most players are participating in event in the town hall. Join a match and see how often you run into the same players.
So, is the community dying? No. Has the player count decreased, like all online games? Yes. Is there still a community to play the game? Definitely.