I think that maybe blandness is their rebellion. The best way to rebel against our excesses of the 90s is to turn down smoking, drinking, drugs and any kind of risk.
I suspect the scene that comes along to blow it all away will be like when punk killed off disco (the worst music scene there's ever been).
The relates to my above comment, but music and new music styles and even fashion are driven first by technological innovation. A good example is how synthesisers and drum machines drove music into the styles of the 80s. New instruments like that are hard to come by these days.
There hasn't been a serious cultural movement like new wave, britpop or punk etc. since the mid 1990s. I wonder if this is related to the rise of the internet, napster, social networks etc. as this all started at the same time.