Dang Hoarders.

The Excalibur birthday chips were also produced in the "massive quantity" range and have all disappeared from the casino floor.

Even tiny little Elko has had limited editions produced 1997-2001 in 2,000 Qty issues and they are becoming scarce in play. 64,000 people a year fly in on Casino Express (my guestimate) if 2% of the people take home just one chip, it fits that all would be gone. (just ignore someone like myself bringing home $150 worth.) Those chips are scattered one to a home from Ohio to Seattle.

Caesar's and Strip Las Vegas properties have a much higher volume of visitors, so it fits that at 2% taking home a small memory, the chips would eventually vanish on their own, without collectors.

Michael is right, there is a source for profit to the casino, especially on the higher value chips.