Well some people are busy learning then farming the new extreme trial or farming the new PvP series (and yes many casual players do this and a new map was released for it). I've been doing both. A lot of people also farm hunts around this time, and many others aren't completely finished with OC or Cosmic yet. For that reason, I'm sure it's out of consideration for the people who are doing the content that they released in 7.3.

I'd say they might be learning the Unreal trial but my experience with it so far is it's a 1-pull-to-clear. If you can do the normal version of Seiryu you'll probably get through Unreal.

I really don't think SE worry too much about subscriptions. If they did, it would definitely be a lot worse, because I remember WoW did it way worse to the point people fled to this game over it back in Shadowbringers. Also, if they were doing it for subs, it's not as if it's working for them considering the dropoff since Dawntrail release.