Uhm, while Sailor Moon was the most popular, I'd think it's safe to say that Card Captor Sakura was what really kicked of the whole thing. I mean, it was the work that made CLAMP famous, so there's gotta be something to it.
I am personally not happy with feminism spilling in and claiming the laurels on that one, but maybe that's just because in the west thrid wave feminism is such an obnoxious disgrace that brings shame to the entire history of the movement. Mostly it was the universal reception of CCS with both the male and female audience that made the Anime industry do it's usual thing of "oh god we found something that is commercially succesfull? MAKE TEN BILLION VARIATIONS OF IT!"
This is a mechanism inherent to every center of cultural production, but the fast and merciless pace at which the anime industry moves kinda brings that up to a whole new level. In this enviorment commercial success is everything, all ideological stuff is just something you add later so you can sound smart when giving interviews.
In the end it's a power fantasy with a female protagonist going with feminine aesthetics, that has their roots in the Super Sentai (or "Power Rangers" in the west) genre, as most of japanese superhero-antics do. The concept of giving every member of the "hero team" a distinctive color kinda stems from there as an example.
Altho aside from one parody I have not seen a "magical boy" anime yet, there are just male characters sometimes appearing in the regular shows, which is good enough I guess.
Also the genre itself is currently going through it's subversion, trying to shake of that "series for little girls" image by giving you death and despair in Madoka Magica and Mhou Shojo Raising Project.
The male with feminine hobbies is not an invention of that tho. Even in 80s delinquent manga you have super-hard-boiled badasses have such hobbies - mostly hobbies that they were mocked for from others, which led to them becoming delinquents in the fist place (by beating up the others), but without abandoning the hobby. Mostly used to give them more character and stuff.
Tbh I think the otaku community as a whole doesn't give much of a hoot about gender conventions - I mean, going by the porn quite a lot of them fap to I doubt they even limit their aesthetics by what is commonly viewed as "normal sexual biology". Generally, with anime having been so extremly niche in the west for a long time, most of the fanbase kinda took on the "weirdo" idenity, so if you are already branded a weirdo, you might as well stop caring about whatever else society says about certain conventions.
Back to topic: feminism had probably nothing to do with it. They found something that had great appeal to the general audience, and as 50% of the potential maximal audience is female, they just aimed at that with a stronger focus on feminine aesthetics in later shows.
Also I find the "they just want the male audience to drool" argument weird. Do those people actually know what a REAL "drool"-show looks like? Like, High School DxD or Monster Musume? And those are even rather harmless examples. Magical Girls are maybe the genre that's the furthest away from it tbh.
Also there seem to be some villains in the new mode, but nothing with charisma or personality, just low level monster-grunts. But maybe there's more to it when we see it hit the PBE...
