If you ask me, there is no such thing as idol anime. OK, maybe there are anime about idols, but that’s not what idols are about.
Idol anime is the new slice-of-life. Which is to say, English language fans can call things however they want, but they are probably wrong when they do.
Basically, it comes in the form of the media-mix IP Love Live, which spawns a bunch of anime, manga, games, music, stage events, whatever. That is par for the course for a lot of the media-mix IPs dating back to the late 90s or 00s. What’s unique about Love Live and its ilk is that they are focused on doing stage shows and live events as a driver for the IP. It becomes a way to reward and reinforce fandom this day and age, it is more engaging to fans (and in ad terms, it drives fans with massively high engagement). Also otaku kids in Japan these days are more about social and networking (and I see that overseas too). Live events themselves also have a lot of pluses in this day and age of seiyuu doing multiple roles besides voice acting, but that’s besides the point.
Invariably most if not all of these “idol” IPs engage its characters primarily, as my non-anime-nerdy friend would say, is like how a professional wrestler (in the WWE and NJPW sense) are like characters performed by the wrestlers, who would have these matches that are dramatic performances and deliver what passes for content to the audience and fans. I don’t know why people think Love Live was the first “idol” thing or the last whatever it was before, but there was definitely some kind of awakening in the west where people “get it.”
The popularity of Love Live and the fact that the IP bills itself as an idol story probably coined the term as such. But the mistake people make is to think Love Live is an “idol” thing. It isn’t. It’s just another media mix story with people who want to be “school idols”–just like how the characters in GaruPan are practitioners of “tankery.” It’s a made up thing that is as close to real idols as just teenage pretty people singing and dancing, trying to make it in some contextually fictional entertainment setting. SIF and Love Live are a work of fiction. But somehow people clang on to this “idol” idea and won’t let it go.
Part of it is obviously that Japanese idols are a real thing, and it is a cultural phenomenon. But I see more and more people who don’t understand the difference between the fiction and the reality. Just like how people apply the term “slice-of-life” to, say, Wake Up, Girls! or something dumb. At least in that verbiage misuse, it’s a made-up-term associated with nothing now being associated with something. “Idol anime” and “idol” generally refer to actual existing things, now being used by ignorant anime nerds to associate with totally different things, regardless of how relevant they are.
You can see this person who complain how calling “Revue Starlight” is misleading people, and it’s obvious. I wouldn’t call Utena or Sakura Taisen an idol anime either, but they are quite similar as Revue Starlight. (Would someone call Girls und Panzer a war anime? Or a tank anime? I guess it’s an anime about tanks, more precisely, an anime about fictional tanks?) But the real injustice here is that it pollutes the discourse on actual Japanese idols, as they are nothing at all like the stories portrayed in Love Live, IDOLM@STER or obviously Revue.
This is also how you get Aqours fans telling their management to not “overwork” the idols. [Which is, by the way, the most sanctimonious, paternal bullshit I’ve ever seen in western seiota fandom, and I’ve been in this fandom since the 90s.] This is not that different than someone who doesn’t know about actual tanks, and thought Tankery exists and a team of 5 people can service 7 tanks in a week, and it’s okay to shoot tank shells at each other???
I don’t know, a lot of this fictional stuff (eg., anime) are only meaningful if you have enough real life experience to contextualize the content. It is real sad if you don’t… It’s like people learning about Japanese idols from anime, when there are tons of real people who are actually in the scene they could read from. It’s fine as a gateway thing but it cannot be your only thing.
PS. I have maybe like 3-4 different draft ideas on this topic in this year alone. It’s really bothering me because while it’s good the Love Live’s popularity is a tide that raises all boats, so to speak, it also brings on a lot of people who are just plainly clueless about idol fandom, culture, and the things those idol IPs try to evoke, and there are not enough school teachers to feed the hungry masses on the Reddits of everywhichwhere. It’s as if only youtubers are their teachers on this stuff, LOL.