With the fact that anyone with a laptop these days is a musician, was the downfall of any really good rock and roll. People spend too much time with the software, instead if taking a guitar and an amp and experimenting with it. When you are alternating between learning a DAW and playing an instrument, there's a loss of creativity.
With actual music, physical, and a band of idiots that don't know what they're doing, if you stick with it, just past the point of where you say fuck it and give up, right on the other side all of a sudden things click and a magic moment happens. A lot of these older timeless bands had time. They didn't have to worry about $3000 mortgages, school, jobs. They had time to perfect their craft. I think more importantly, in the 60's and 70's was the vibe of freedom, and not having the stress the younger crowd has these days. Stress kills creativity.
I also think shows like American Idiot and all those other singing shows helped kill music, along with computers. Most of these idiots can't play an instrument, yet stand there on stage with a guitar in hand, don't write their own music, fake playing guitar and all the suckas in the audience have no idea. That BS disgusts me.