The late '50s and early '60s was an interesting time for American musical tastes. Listeners who considered themselves hip embraced a wide variety of styles, from the calypso of Harry Belafonte to the bossa nova of Antonio Carlos Jobim and even the chanson of Jacques Brel. If they listened to American pop it wasn't Elvis or Little Richard, but Nina Simone, who dared expand her repertoire beyond jazz to include spirituals and art songs.
Then the Beatles showed these Americans that they had nothing to be ashamed of with regard to rock 'n' roll, which at the time had already faded from the charts, anyway. As Louis Menand points out a recent issue of the New Yorker, more than any other artist, it was the European Fab Four who taught Americans to appreciate their own pop culture.
In the end, European pop culture suffered for it, and not just in the U.S. Americans, hip and non-hip alike, went on to essentially ignore any pop culture movements that weren't American. Attendance for foreign-language movies, never high in the first place, declined steadily, and no one buys chanson or calypso anymore. As the hegemony of American pop culture grew, it competed with and sometimes supplanted native pop styles.