In short, RCC is "dead", but it doesn't realize it yet. It's not the first RC forum to die a slow death, and I'm certain it won't be the last. Part of it is because new/better forums get created every so often, and people start flocking to those forums. Part of it is that people get sick & tired of the politics of a forum (such as forums that are overly Republican-heavy (this one), or Democrat-heavy...or the age-old Ford vs Chevy people), and they want to get away from it.
And, finally...the most important reason...part of it (possibly the biggest part) is because people get tired of a particular area of RC, start getting interested in other areas of RC (for example, earlier this year, I finally realized I don't really care much about "going slow"...I much prefer to "go fast", this I started getting into NPRC drag & speedrun cars...so, I sold all my crawlers, as well as the crawler I had built for my stepdad (he's also lost interest)), and, as such, they have no need for a forum of the prior interest. That's when they search out forums that have greater content in their new areas of RC interest. I know my days are numbered in the RCC forum...partly for reason #2 (I'm VERY anti-Trump), but mostly for reason #3 (the only thing 'slow' in my life is my soon-to-be ex-wife)...although, for some unknown (to me) reason, I'm still here.
~ More peace, love, laughter, & kindness would make the world a MUCH better place