The coronavirus hit the Nashville music industry hard this weekend, taking the life of country singer Joe Diffie and sending Americana singer-songwriter John Prine into critical care.It escalated what might be viewed as typical loss-of-life cycles: Jan Howard, 91, died March 28, the day after her 47th anniversary as a member of the Grand Ole Opry. Her death wasn't related to the virus.The news about Diffie and Prine was particularly jarring, with announcements coming two hours apart.