ORIGINAL: K-Bob
It could be that in most cases gas engines are used on ''giant scale'' or at least larger than your typical electric or glow airframe. The amount of participation from this demographic has, for the most part, long left RCU. Just go to the Giant Scale forum and look at the number of participants and the level of expertise of those who do participate.
Other sites, whose links would be censored if I typed them here, have stepped up and filled in the gap.
I follow several other sites and reduced post counts appear to be a general pattern. Frankly the answers given here on RCU are often of a better quality and in more depth than what appears on some of those other sites. At least here brand loyalties are still under check where on some of the other sites, if it ain't DA it ain't worth flying ..... and they won't let you forget it!!
If there is a problem it would be burn out from some of the regular posters who are still here. You don't see the in depth answers that were once so common. My guess is that most assume the poster of a question should do some research on their own when a suggestion is given.
There is still plenty of talent here to answer questions. W8YE, Pe and a few others could handle the question load by themselves if necessary. The point .... questions still get answered when asked.
I don't miss the verbal wars and constant snipping that went on when TOM was here though I do miss his expertise.