The type of people posting these questions on reddit today wouldn't have been at those parties yesterday, so I don't think we can extrapolate some overarching theme here
My anecdotal experience with two children who are young adults is that there are still house-parties (nearly) every weekend at high-school, but that there's a lot less drinking, and they're a lot more open and mature (i'm not sure i would have enjoyed being a trans kid in a 90s high school)
I'm not saying the kid who posted this is a 100% representative sample, but at least in my experience of the teenagers I know, childhood has changed drastically in the last 25 years.
If you look at some of the poster's comments there, he laments that even when he does go to house parties, everyone is just sitting around on their phone. I have certainly seen that.
My anecdotal experience with two children who are young adults is that there are still house-parties (nearly) every weekend at high-school, but that there's a lot less drinking, and they're a lot more open and mature (i'm not sure i would have enjoyed being a trans kid in a 90s high school)