[nl]

I agree with most of your points.

My personal sense is that rave was the last postwar subculture

I'm unconvinced. I think that there have been numerous post-rave subcultures, but the time difference between "cool" and "mainstream" is shrinking.

Cosplay, trail-running and "start-ups" are three subcultures that jump out at me as things that have gone through this (I'm not overly familiar with cosplay, but it seems to me that it has gone from nothing to something people make money from).

Maybe you are thinking of just music though. Dubstep had it's 6 months of cool before making mainstream, maybe?