Most of the sites I read have had similar issues. Facebook groups have taken a ton of traffic from forums, and forums splitting into subgenres have certainly hurt places like this too. This has spawned A/B/C/E bodies only, as an example. Or Yellowbullet, tuning into Turbobullet/Phantombullet, etc.

Like many of you have mentioned, the Facebook groups have more activity on them but the signal to noise ratio is much worse than a place like this.

It also doesn't help that this hobby specifically is mostly an older crowd and people are getting out of it for various reasons.

I follow a dirtbike forum as well and that's about the only one I haven't seen lose traffic over the last decade or so.