People will say it's because everyone who enjoys the game is busy playing it, but I've dragged myself on all week just to do some roulettes and the queues take so long to pop that I just give up and log out. The CWLSes I'm in are really really quiet, PFs just sit waiting for healers, etc.
The main story that everyone's cared about this whole time is over, and DT did not carry the mantle very well if reactions to the bad writing and new lead character were any indication. Story fans who kept subbing for the narrative are gone. Gameplay bros liked the direction of a lot of the battle content, but like always there wasn't enough of it to keep anyone entertained very long, so now here we are again, in the post-expac lull with 2 more months of nothing to look forward to before we get like... an alliance raid and that's it? This game's problem isn't even hard. Just give folks more things to do so they don't get bored and quit. That, or have a compelling story so they feel compelled to resub for the next chapter. You can't be a story focused mmo with a bland story and bland/lacking gameplay and then make the surprised pikachu face when people don't want to play anymore. This happens so often that you can see the trends on steamcharts. It's happening right now. Big influx of people for the expansion, but then there's nothing to do afterwards so people leave and the game has like a 30% drop.

Hell, as I typed this out I was just sitting in an expert roulette queue. 8pm on a saturday night, 10 minutes and counting. I've been the #1 role waiting list number for like 7 minutes lmao. But yeah! I'm sure allllllll the people who love the game are totally just online and playing it, right?