to comment on the Car aspect noted by the OP

I think a lot of younger people (basing this on my son, 24, and his friends) are not as into cars as I can remember being as high schooler. (ask him how many cylinders, displacement and whether the 2004 volvo he drives has (5, 2.5 l, yes) and he could not tell you. not sure why?

to put it in bike terms their approach to cars is like the dutch approach to bikes, they are tool to get from point a to point b, and carry stuff

that said locally there is pretty good attendance to micro car shows...last weekend 4 blocks of the micro downtown area near me (lincoln ave for locals) had a hot rod, woodie and lowrider show....super nice. the hot wheels dodge cab forward van/pickup with surfboards was super nice and some nice woodies

but I don't see my son going to a car show as destination

as for bikes, BMX was king, then he road ss/fg but just gave that bike to a friend who commutes on it and he never got into bikes with shifting, so he has not base for C&V appreciation

bit of a ramble but I think a lot of it is lack of hands on wrenching caused by necessity or that you can't do a lot of hands on on modern cars has a lot to do with this