Within hours of when its season-opening concert by The Philadelphia Orchestra was set to begin, Carnegie Hall was forced to cancel that performance Wednesday after its stagehands, represented by IATSE/Local One, went on strike. The unprecedented walkout follows a week of terrible news for classical music in the U.S., in which the music director of the Minnesota Orchestra resigned over its musicians' contract disputes, and New York City Opera announced it was filing for bankruptcy, ending its 70-year run as "the People's Opera." The Philadelphia Orchestra, locked out of Carnegie and still recovering from its...