Why the huge disparity in revenue?

The U.S. Open's advantage over Wimbledon is largely due to two revenue sources: sponsors and tickets.

Wimbledon has always had a sense of tradition. Wimbledon favors long-term partnerships with trusted sponsors like Rolex, Slazenger, and Robinsons Barley Water, which are not allowed to advertise directly on the grounds. 

The logos on most courts are black, which are barely visible in order to highlight the beauty of the lush light green grass and dark green border. On Centre Court and Court No. 1, the logos are white but minuscule to anyone who isn't seated in the front row.