>>11756366
To me seems to me it's more like the Touhou fandom is stabilizing itself.
Take a look at the pic--You've probably seen something like it before by trolls trying to tell everyone about how Touhou's finished, except this one doesn't compare it to Kancolle's search results. If you look at the Touhou trend closely, it absolutely skyrocketed in 2008-2009 and then returned to previous levels by 2010. After that, the search results for Touhou have been hovering steady since.
If this is indicative of what's happening now, then the steady decrease in doujin circles is telling us that the Touhou bubble has gradually deflated to a sustainable level, as opposed to outright popping.
In other words, it's reached a point of equilibrium, now that the transient attention whores/profiteers are trying to find onto the latest trend, with the remaining artists mostly consisting of those that genuinely enjoy the series instead of trying to exploit its popularity. This is probably the kind of doujin community that ZUN wanted this entire time.
What I'm more worried about is that Kancolle's popularity bubble is going to burst instead of gradually deflate. If other anime fads are any indication, then once the Kancolle anime is done airing, the circles are going to end up leaving in droves.