Douglas Wolk theorizes the existence of “peak rock” a la “peak oil”:

For those who aren’t familiar with the problem, peak rock refers to the point in time where the maximum rate of production of global rock ‘n’ roll is reached, after which rock music enters a period of decline–you can map it out as a Hubbert curve. Rock ‘n’ roll was once considered to be a virtually limitless resource–what we call the Neil Young theory, that “rock and roll would never die”–but what we’ve been seeing in the past decade or so is that it’s actually non-renewable, and some experts now believe that peak rock may have been reached in the early ’90s or possibly even as early as the late 1970s. It’s not like all the rock is gone, but it takes more and more money and effort to extract large deposits of rock, and the remaining major labels have been forced to rely on diminishing reserves of fossil bands.

(Quoted from a 3-minute talk he gave at Experience Music Project earlier this year (about independent-label music in the ’00s)).