A number of articles have been written on the fragmentation of the music market and the lower sales peaks reached by hit albums. There are a million and one subgenres and sales of hit records just aren't what they used to be. Semi-popularity is easier to grasp, superstar status is less attainable.

BusinessWeek Online's Jon Fine is the latest to chime in on the phenomenom. In "Rockers, Keep Your Day Jobs," Fine compares today's landscape against the star-friendly "symbiosis among rock radio, record labels, and the arena-concert circuit."

"In the 1970s their interplay enabled the emergence of a new class of megastar band like Led Zeppelin. But of nearly equal importance to the music business, it also gave rise to a cadre of second- and third-tier rock bands that, despite critics' complete derision, sold zillions of records."

And today:

Rock radio is increasingly a victim of fragmenting demographics. The sole genre posting sales gains last year, according to Nielsen SoundScan, was Latin. Arena rock shows that once promised spectacle for less than a sawbuck have bloated into elite affairs resembling closed corporate events. ... Today's key entry points for music consumers are iTunes (AAPL ) and ringtones. The former favors singles over albums and thus further unbundles rockers' preferred medium, and the latter is peculiarly inhospitable. None of the top 10 ringtone downloads of 2005 came from rock acts. Hip-hop now owns the artist-as-icon phenomenon."

True true true. The middle class is growing. The ceiling is lower and the floor (with the help of tools like MySpace) is higher. The billion-dollar question is this: What's a successful symbiosis in today's industry?