Ultimately to me this all boils down to "the times they are a changin." Or in reality "the times they have a changed." As a 43 year old musician (and amateur sociologist) whose heyday was 1995-2003, it was easy to see back then that rock was dead/dying and that all of a sudden no one really gave a crap about live music anymore. There was a post in this thread from a guy who grew up in Jersey in the 80's and how the live music scene was awesome back then. So true, mainly because of so many sociological forces at play that converged at a perfect time to be a musician. these were:
1) People were way less uptight than now.
2) No one was distracted by 24/7 technology
3) Musicians still wanted to play live music
4) Music, IMO, simply meant more to us back then than to the youngin's of today (generally speaking....of course there are exceptions on the individual level).
5) Cops, while still in the business of harrassment, just were a little bit cooler back in those days. As a society, we weren't on the brink of a nervous breakdown due to fictitious and constant propaganda about so-called "terrorism."
Ultimately though, while I think that the music scene is completely dead for anyone over 40 (again, generally speaking), to me it seems quite a few of the kids of today are playing in bands and trying to follow the dreams we all did back in the 70's, 80's and 90's. It's just way, way harder for them due to negative societal inertia.
Oh yeah, and the fact that many are playing horrific dethcore and all sound the same

.