The Detroit Symphony is taking its time in the search for a new music director to replace Neeme Jarvi – in fact, the orchestra may play two or three full seasons without an official leader after Jarvi departs next summer. So why the delay? Part of the problem is the lack of great conductors in the world, but “a more subtle issue has been management’s inability, dating back at least a decade, to lasso enough A-list guest conductors and nurture relationships that might blossom into a music directorship.”