Rock music is falling off American radio airwaves. “In the last four months, radio executives have switched the formats of four modern-rock, or alternative, stations in big media markets, including WHFS in Washington-Baltimore area, WPLY in Philadelphia and the year-old KRQI in Seattle. Earlier this month WXRK in New York discarded most newer songs in favor of a playlist laden with rock stars from the 80’s and 90’s. Music executives say the lack of true stars today is partly the reason.”