The game's not dead. I see new players all the time in Haven. My guild continues to fluctuate in membership, just as it did years ago.
However, the player base seems to be in continual slow decline ever since the Steam launch, except for a couple of bumps such as release-2013-07-30.
Also, a lot of veteran players keep their parties locked for various reasons: not wanting newbies, needed to go away from keyboard, etc. We had a thread about it recently.
I recommend that you start parties, keep them public, and befriend the people you meet. Or join a guild and do runs with your guild mates. Either way, there are still more than enough players to keep you occupied. Good luck.
/burps