I don't think it ever really leaves you, but I also think that we're growing up later because we're allowed to and/or it's facilitated. It seems as if your twenties really are just an extension of your late teen years now.
I've had this whole thing about my generation seeing the baby boomers "hope I die before I get old" attitude and seeing that it's great, so long as you die and that you want to. Otherwise you just get older and become what you didn't want to be. The older generation/your parents.the establishment. Therefore we've devised a way to remain children for a lot longer. Growing older but not growing up. But maybe it's not.
Maybe it's more to do with the economics of the last 30+ years? If large numbers of people can't be guaranteed a level of living because of the job market/the wages paid at the most basic level, then I'd think it's natural to not engage in a lifestyle which requires that. Or maybe it's the reverse? Having more disposable income means that we can spend it on things we'd otherwise have to do without and, therefore, would have neither the time or the inclination to do/play with.
Or maybe it's advertising? If you constantly sell youth as the pinnacle of the human experience and the desire of everyone who wants to make money/be loved/be attractive/have friends/etc you have to expect people to do what they can in order to stay in that area/condition. Pretty much everything is sold to children now even if they're not the end user. Do you think the screens/dvd players in the back of SUV's are there for adults?
Maybe it's to do with women's lib and the importance/equality of womens education? With women less likely to settle down/get married/have children/etc at a younger age because there are more opportunities for them/they have greater aspirations/expectations for their own lives it allows men to do the same. Without being 'forced' to grow up, men have greater freedom to mess about and do as they please.
Or, maybe, it's simply a progression of the "hope I die before I get old" adage of The Who and, as greater social freedom becomes the norm, so those boundaries are, eventually, pushed so what was once extreme or avant garde becomes mainstream and/or the establishment?
Maybe it's because of the fear of failure/blame culture? Everyone is judged on and about everything by everyone. The most popular entertainment programmes across the world are all based on being judged and laughing at the clowns. Reactions are instant and lasting. If a boxer loses a fight people will talk about him being finished as a challenger. If the next big thing doesn't constantly improve until they become the best, they're done. Failed. "Oh, remember when (s)he was going to be the next ...." (S)he could still be among the very best in his/her field. But if (s)he doesn't come along and fulfil expectation? (S)he failed.
It's natural to not want to fail and if you're being told that failure is final, then why risk trying? Better to stay with the familiar.
Maybe our toys simply grew up? Our toys are more adaptable now as it's software rather than hardware. If the toy train set my dad played with as a child could've somehow become a train set for adults, then maybe he'd have continued playing with it?
Anyway, I've gone waaaay above and beyond what I meant to start with, so I'll leave Gab's thread alone.