I'll say it's a vicious circle. Most shows used to be open through Sunday, but so many dealers left on Saturday or early Sunday that the shows were ghost towns on Sunday. So they dropped Sunday. Now the dealers leave on Friday or early Saturday and the show is a ghost town on Saturday. One show tried Wednesday - Friday hours. it was a disaster. no public Wed or Thursday, and when people got off work Friday and came to the show they found it closing down. The incentives work better than the penalties. The ANA tried the penalty route. They informed the dealers that those who left early would be fined and next year their tables would be in the back of the hall. Well a bunch of the dealers still left early including the major dealers withthe multiple tables just inside the entrance. The ANA tried to levy the fines and told them they would be moved to the back. The major dealers said "well then we just won't take any tables and we'll just come work the floor dealer to dealer. Well since that represented a lot of tables, and the big dealers were a major draw for the show, so the ANA caved. No fines for the big dealers and they could still have their front tables. The small dealers were fined and moved to the back of the hall. Money talks.
I went last year on Friday and will try to do so again this year. I picked up some international coins that I was unable to find elsewhere, even when I went to the ANA show in Philly. There will be basically no US coins.