"When I played there in 2001, there was many of those chips in play as "regular issue" $5 chips. Part of the problem is that they are very common."

New collectors who were not collecting in 2001, and who may not have this chip at the time it was placed for sale on ebay ... may not know how many chips were available. All they know is that someone else is bidding against them ... so the assumption is that chip may be worth more than what they are bidding. Once these two head-to-head bidders have the chip ... there is no future bidding interest for it since the demand has been satisfied.