Peter Pan Syndrome is still a thing, but very nebulous. Generally handled as a deprecated condition of prolonged adolescence and inability or unwillingness to shoulder "normal" adult responsibilities. Particularly applied to men, as the gender of the character implies, drawn from the famous "I don't want to grow up!" cry of the titular character. I believe a portion of it is indeed based on the extended adolescent irresponsibility of my and younger generations based on our egocentric view and the relative success of marketing... But I think a far greater portion of it is due to the social contract being offered to such young men is simply far, far worse than it ever was in the past. In short "the deal" offered for growing up is insultingly bad enough that a lot of people reject it, consciously or not.
I believe it predates your generation by at least two... given the cultural worship of youth, it wouldn't be surprising that many see childhood as a favorable state of existence... but in reality, children have very little power, and it's quite a disadvantaged state in comparison to being an adult.
Conceptually it predates my generation by more than two, Peter Pan is not a new story, and it wasn't a new idea at the time. However the wide-spread accusation and or recognition of it is more closely tied to Gen X / Millennial groups. And you can kind of associate that with the pop-culture heroes of the time, such as the eternally adolescent Bill & Ted or Beavis & Butthead.
Yes, I knew I was missing something when I didn't watch Beavis and Butthead... there's always YouTube reruns I suppose.
My favorite author Adam Phillips, believes it is a mark of despair within the culture when children are idolized.... in other pontifications he goes on to elaborate that "what we really need are more compelling examples of frustration"... if you live in a culture which values constantly catering to and meeting instant gratification or instant satisfaction... you have something like what you have today in the culture at large... and it's like a handicap to creativity or originality or living an interesting life... if one cannot bear frustration, one cannot begin the process of creating something because of the superficial overfeeding, in essence.... I'm not sure if this ties in with the peter pan thing, but it seemed related in my mind...