Most will leave regardless, eventually. If the forum's administration continues to stay the way it is, I don't expect things to become better here. The OGs already left, when sig campaigns came around.
Think about this: Lauda left, Lutpin is
?, Zepher died(fuck.), same for Bruno(RIP), idk where escrow, tradefortress, or half of the OG ogs even are. Bitcointalk is no longer the iconic place it once was, it doesn't feel like the same forum where the likes of Hal Finney used to go around and speak with the community, hell even Satoshi was in the same forum; he fucking created the forum and now its a shitpile if anything.
Quite a few donators are still active, as in they're at least logging into the forum from time to time, although don't seem to participate in the discussions much. At the end of the day, if you've been around long enough, you'll see repeated content, that's just natural. We continuously have new users signing up, and asking basic questions, because they are the same type of questions we might have wanted to ask several years ago.
I do think this forum is better managed than a lot of the others on the internet, though you could potentially call me biased on that. I know at least there's staff here that are actually passionate about the forum, whereas other forums they might be doing it for the illusion of power or just getting paid. At least, most of the moderators I've had a chat with are passionate about how things run around here.
Of course, certain areas of the forum are less than ideal. I mean the Altcoins section is in particular pretty bad, however I dedicate a lot of time myself scouring that place, and moderating there, as do a few others. Some days I'm taking hundreds of actions in that section alone, and I'm also one of the patrollers. That's ignoring the fact that there's several others likely doing the same thing.
Signatures won't be banned because theymos knows that's the start of the end.
I do believe he's alluded to liking the idea of the forum having a sort of eco system. Though, I might be talking through my arse there as I can't actually find it, but that might be because I'm not searching the correct phrases used. I think theymos said something along the lines of liking that it's a thing, but if it becomes to much of a problem would have to look at dealing with that
