NEET is a term that came out of the 90s in the UK, and was a borrowed acronym in Japan after that. not a new term by any stretch of the imagination and is barely younger than the modern internet itself.
In academic circles, sure, but it’s fairly recent that it has been seeping into internet language, mostly through 4channers who started using the term for themselves in a self-deprecating way.
its often used in circles relating to japan for awhile, mainly anime as shows like Welcome to the NHK(2006) cover it. still technically speaking, not a new term, and i wpuldnt be suprised if /A/ on 4chan used it for more than a decade now. definitely not recent.
Well I’m sure it’s been in use for a while, but not in mainstream internet lingo is my point.
Speaking for myself, I only learned about this term a year or so ago, because I remember looking it up, and I remember thinking: huh, so there’s a word for that now. Since then, I’ve seen it come up several times, almost always in greentext posts like this one.