Yeah well, she just got 9 uploads in less 2 hours since your post and mine, so yeah, also I like Touhou as much as the next guy in Danbooru, but I have never understood why theres SO many fan-art and keeps comming
Probably people love Touhou so much because of its "estrogen overload" factor, and besides, ZUN himself was more of a musician than an artist, so his nominally "official" art every now and then gets some "upgrade" from the fans. And with such scant information from the manual, fans gets a leeway to have their own concepts of the characters, leading to a near-endless stream of fanart and doujin works. And yes, speaking of "approaching 100,000", as of this writing the "touhou" tag alone, at 94000+ posts, is the third-largest tag throughout Danbooru (just behind "long_hair" [121000+] and "breasts" [100000+]; both of which are "general" tags), and THE largest "copyright" tag (way ahead of 2nd-place "original" [30000+]).