I'm with the opinion of the OP. Things do seem to have slowed down considerably on this forum. But it's not just here. The other two forums that I belong to have slowed down, with one becoming almost deserted. I don't believe the reason for this is summer or any kind of seasonal effect. I'm convinced that the cause is Facebook Groups.
Facebook has groups (often several for each subject) that are hopping with activity. As you would expect, some of these groups have populations that teeter on the edge of illiteracy, but others have some renown experts of the drum industry - new and classic. These guys are a treasure trove of dependable information (often with cited references), and that's what attracts me to those particular groups.
So, that's where I think our audience has gone. I don't think it's a result of format changes or any other intrinsic fault of the individual forums (except for one, which I will not name). Facebook is huge, and people can be entertained not only by their specific interest group, but by news, entertainment, politics, music, and movies - and all on one site.
GeeDeeEmm