While I certainly don't think rock is dead, Shreddy has some good points here. The industry has changed a lot, and bands don't necessarily get the same breaks these days. Record sales are lower, and record companies are VERY picky. There are tons of bands from the 60s 70s and 80s that would not have got the same deals today.
Another thing I think actually plays a part is social media and how freely information flows these days. A lot of the mystique around stars has been lost after the rise of the internet and social media. Everyone "knows" everything about everyone. When I was a kid the rock bands we loved were all larger than life, much because information about them was very restricted. We were lucky to see a few pictures or read an article in a music magazine every three months, and if we were really lucky we'd see them on tv every now and then. Now, everything is there, every performance, every interview, every blunder, every success, is there at the click of a mouse button. The stars of old lived in a mysterious world of glamour, excess, parties, money, good times and sex. All the things that we as kids thought we wanted and considered to be the true meaning of life. (Just think of all the absolutely INSANE stories that were told about Kiss. I remember a friend of mine telling me, with great sincerity and conviction, that some of the women depicted on the cover of "Love Gun" were dead because Paul Stanley had f***ed them to death! The fact that the cover is a drawing didn't matter...) Now the stars better behave, or else they will be busted. Not that they necessarily behave that differently from the heros of old at all times, but the mystique, the allure of the stars is gone. My kids have different heros. Whether this is good or bad is an entirely different discussion, but I don't see rock as being larger than life to the same extent as before.