Outdated technology is probably an issue for sure.
The 10 page thread max before lock is an obvious one. It is a natural point for people to stop posting.
Probably should ease up on some of the arcane rules. Like seriously, the word editing by mods and time spent on it is nutzo. But easing up on some of this might help and keep people interested. Might make them feel like they are being baby sat.
And last but certainly not least, it just seems like most of the vets have gone away for one reason or another that really prompted people to post when I first joined. They were all tremendously helpful and there were a ton of them. Now there seem to be relatively few.