From 2003:
The “untheatricality” of rock music is a complicated subject about which I’ve never gotten around to writing. It’s far too complicated to go into in a short posting, but I can say that to blame the decline of the Broadway musical on rock is to mistake a symptom for the disease. What happened in the Sixties was that the old-fashioned standard-style ballad ceased to be the lingua franca of American popular music–and that nothing replaced it. Instead, our musical tastes shattered into a million pieces….
Read the whole thing here.