It seems like around '07-'08 was when there was this big awareness in our community to learn about proper hair care and to grow long hair. It was fun initially to learn new concepts (satin/silk scarf sleeping, protective styling, protein-moisture balance, hair types, etc.) and we saw women growing relaxed hair to long lengths. Then the natural hair explosion started and we spent many years exploring that as well. I think now things are dying down because we've sorta accomplished our goal. WE now know that we can grow long hair too using the right techniques and practices. So now, many just lurk or have moved on to other things. The haircare community spilled over into YT, FB, IG, and other SM arenas so that also takes away from forum traffic.
Personally, I've never had long hair my entire life. So once I achieved what I once thought was impossible and it became the new normal for me, I got busy with other things. Just like any other hobby, we pick it up and put it down at different times. Or leave it completely, depending on what life throws our way.
I'm grateful for what I've learned here and on BHM. I still find the old threads valuable and don't really see a need to rehash the same topics over and over. And now I can pass it on as common knowledge to my daughter/niece etc. However, I still find it a fun hobby for me so I try to participate. I think others may not. And I know that there are many more who'd rather just lurk and learn. Especially since almost all of the "issues" have been explored/discussed and remedies tested and distributed.