It's the sheer frustration around the many unfixed bugs and missing features that's the biggest thing to me.
There are two different approaches you can take and make the community happy. You can take the big dev studio approach and say little, but fix things regularly and competently so that people can expect bugs to be fixed in a reasonable timeframe.
OR you can take the small indy dev approach and communicate regularly with the community and explain why bugs are there and that you're working on them, but they're complicated to fix, and maybe giving some temporary workarounds, but assuring everyone that they ARE being worked on, thereby building a rapport with the community.
But the worst case is having the speed of the second but the communication of the first. There are bugs that have been around for literally years. There are bugs on the issue tracker that have been reported dozens of times, but because the issue tracker doesn't count anything that doesn't hit a minimum popularity threshold, they just vanish. It's like they're actively trying to spit in the face of their community, many of whom really do want to help them.
If someone quits because they're not into FPS combat, then fine, that's just life. But if someone quits because they get crash after crash in repeatable ways that have been posted multiple times but never fixed, then that loss is 100% fdev's fault. And that is EXACTLY the sort of thing that kills a community, and then a game.
I don't want to be down on Elite, but it's really hard to see any upside to the approach they've been taking.