The truth about Broadway ticket prices

Why do Broadway tickets cost so much? I feel like I've been asking this question my whole life, but prices continue to rise like an entertainment arms race.

For instance, if you'd like to see Denzel Washington in August Wilson's Fences, a premium ticket goes for $351.50. Denzel's a great actor performing a great play, but for that kind of money a family of four can spend the day at Disney World.