WHEN IT BEGAN THREE DECADES AGO, the authors of the Immanuel and Helen Olshan Texas Music Festival—commencing this end of the week at the Cynthia Woods Mitchell Pavilion in The Woodlands and the Moores School of Music at UH—couldn't have recognized what it would turn into. The Olshans were devotees of old style music and put stock in supporting developing specialists; they saw no requirement for crowds...