As you're well aware from articles in just about every newspaper and magazine out there, 2004 marks the 50th anniversary of the "birth" of rock & roll. Although not as easy to pin down as the day that Hendrix choked on his vomit or the day that Elvis joined the Army, it's generally accepted that the release of the "Rock Around the Clock" single by Bill Haley & his Comets on April 12, 1954 was as close to a Big Bang event as rock & roll had. (By "generally accepted," I mean "endlessly debated.") Let's think about that for a minute. If you were a teenager on that day in 1954, you are at the very least 63 years old today. In other words, rock & roll is old.
When you look at the changes the music has gone through in the last 50 years, it's easy to notice a precipitous slowing of progression. A batch of new reissues the soundtrack to "Rock, Rock, Rock, The "Chirping" Crickets" by Buddy Holly, Chuck Berry's "After School Session" and, of course, "Rock Around the Clock" help make that abundantly clear. Though the ingredients for rock & roll had been stewing for some time before 1954, that was the year when it became a true cultural force. Sure, Elvis performed his first concerts in July 1954, but they were small and confined to Memphis; it wasn't until the popularity of "Rock Around the Clock" singed the juvenile consciousness that he was able to step into his historical role.
But if you look at the changes that took place between the release of these records and, say, the Summer of Love in 1967, there were seismic transformations on a regular basis. From "negro music" to passing fad to teenyboppers to melodic pop to The Beatles to Monterey Pop that's a lot of ground to cover in a little over a dozen years. Compare that to 1967-1980 and the revolution loses some steam: There's prog rock, arena rock and punk. The next 13? New wave, metal and alternative rock. That's what happens when a finitely divisible source gets split into way too many parts.
If you take the next 11 years, what have we got to add? Fucking Hootie & the Blowfish and the Yeah Yeah Yeahs. That's a Xerox machine just about out of toner.
Hail, hail rock & roll, indeed.