The PVE community has also dwindled since the days of Nim TfB, the fact that you only see a handful of guilds on the PVE progression leaderboards even proves this.
Majority of the hardcore PVPers have gone to wildstar, mainly due to the fact that the PVP there has a lot more to offer than SWTOR currently.
This game's hardcore community is leaving because the devs are merely focused on F2P / casuals and not taking care of the game. If a game lacks hardcore/competitive gamers, it falls shortly after.
I am quite frankly not too excited for 2.9, didn't know I subscribed to play The sims: Star Wars edition....
and yes I'm bitter