Like for many other people, for me the issue is that there's rarely anything to do. Not having any kind of conflict between houses feels strange. So yeah I just find myself looking at the playerlist instead of actually doing anything, it feels like a chore.
The problem with activity isn't that people are leaving, they might be doing so for different reasons. The problem is that less people are joining to replace them. And contrary to popular opinion I think this game has potential. Space arcades/sims are in a sad state in general, FL has unique controls/mechanics that still haven't been replicated, there's clear demand for something like this, otherwise most people here would have already moved on to a clearly better space simcade. It's even more of a shame that people are around, they log rarely during big server events and that's it.
After being away for years and coming back once every 3-4 years I've realised people here have this negative attitude towards Freelancer and weird self-defeatism, it's an obvious echo chamber.
Frankly speaking, when people talk about why less and less people want to play Disco, many of them are way off. Freelancer was already way old in like 2013 when it still had decent numbers. It is a relatively unknown fact that something like this even exists, so even a few hundred bucks spent on ads/promotions would do wonders in my opinion. I assume plenty of people would be down to chime in for something like that, I know I would be. But for now the idea with the mailing list for previous players seems like a good first step. And then there's also the question of this game becoming a better experience for newcomers and so on.