As the fall season begins this month, 13 shows are entering at least their 10th season, believed to be a modern-day record. That includes such programs as “Grey

As the fall season begins this month, 13 shows are entering at least their 10th season, believed to be a modern-day record. That includes such programs as “Grey’s Anatomy,” entering Season 15, and “The Simpsons,” entering Season 30. Viewership for each of these shows is down more than 70 percent from their all-time highs.