>>49801848
>>49802398
You have no clue what you're talking about, or you only know about the western part of the fandom, who are more perpetual Touhou 6-8 fags than even the Japanese.
The beast mafia trio are quite popular, especially for newhus. People are for some reason making a decent amount of MMDs about Saki. It probably doesn't help that one of the most popular Touhou fanartists is a big SakixMiko fan.
Of course, Keiki and Mayumi are part of that discussion as well. 17 and Animal Hell in general have garnered pretty positive receptions overall. Okina is also decently popular in the jp fandom, being basically modern Yukari. Aunn isn't doing so bad either. Everyone I've mentioned so far, by the way, has more fanart in Pixiv than Megumu.
You, like a lot of people, mistakenly think on the idea of "why is a character that's a few years old doesn't have as much fancontent as a character that's 20 years old?". It's kind of a self-answering question.
It just doesn't happen on sufficiently old franchises, with the only exception if a new entry manages to strike through a new demographic it didn't have before. It's extremely rare a character introduced in an old franchise immediately replaces an existing fan's already favorite characters in his mind.