Back in ther olden days, real doubleheaders were played throughout both leagues on the main Holidays; Memorial Day, Independence Day & Labor Day. They were even scheduled on the occasional Sunday. Yesterday, there were NONE of course. The Mets were even scheduled for an Off Day!!!! Is that part of the Labor Agreement? If it is, that's stupid. Of course, today's players are different from those in the olden days. Ernie Banks used to say, "It's a beautiful day. Let's play two!"
$$$
https://bleacherreport.com/articles/665190-the-double-header-why-its-missed-and-why-it-should-come-back
THANKS, Ed! Of course, I know $$$$$ was ther answer. Walter O'Malley was the first owner to put $$$$ first; he started Morning/Afternoon & Afternoon/Night Doubleheaders so he could get more money out of Ebbets Field.