Bill Dwyre, sports editor emeritus of the LA Times (unlike people who will just leave the paper after getting a nice chat with the folks from HR), bemoans the lack of doubleheaders played on holidays.
It's a piece waxing nostalgic on doubleheaders with some delightful anecdotes. But Dwyre forgets the one big reason why teams don't schedule doubleheaders unless they're forced to: they take a long time to play.
Unless you know ahead of time that you've got two Greg Maddux-like pitchers going for each team in each game and nobody is planning to score much, then you're in business. If not, you're likely looking at keeping people in the park for six to seven hours.
I could probably handle that and lot of people reading this wouldn't mind that much time at the stadium. But the average doesn't want to do it. I couldn't picture taking a child under the age of 13 to a baseball stadium for that length of time.
What if the Yankees and Red Sox had played a single admission doubleheader back on August 18, 2006. Game one lasted 3:55. Game two lasted 4:45. Neither game went into extra innings. Eight hours and forty minutes in total. If those games had been played right after another, it would have been a nine hour day. The fans don't get paid time and a half.
I've attended one doubleheader in my life. It was on June 26, 1988 in Oakland. The Twins swept the A's, winning the first game 11-0, and the second one 5-0. I sat in the right field bleachers with my then-girlfriend, a Minneapolis native and a big Twins fan. She made it through the first game and a couple of innings of the second before heading off to some concert that I recall having no interest in attending.
I do recall that it was a very long day. And there were a lot of very hammered people on the BART train on the way back to Berkeley. I look back at that doubleheader as more of an endurance test rather than a fun day at the park.