Some food for thought from Billboard:

"As it stands now the classic rock radio format has seen many of its original listeners age out of its target demographic (25- to 54-year-olds), but remains relevant by posted gains among a new generation.Among 18- to 34-year-olds, classic rock's share of audience in November was up 13 percent from a year earlier, according to Nielsen's Portable People Meter (PPM) survey, which measures radio listening in the top 48 U.S. markets. Jon Miller, vp of Audience Insights for Nielsen, says, "Those are pretty significant gains for a format....In other words: Three decades later, classic rock remains a top 10 hit."

Classic Rock Radio at 30: The Songs Change, So Does the Vibe Remain the Same?

The history of Classic Rock radio website