As I said before it comes down to location and marketplace. I know what I can and have sold them for. I know there are places in New York from a quick goggle search listing for $2999 the way it is, an additional $999 with new side art. If it moves it moves, if it don't, I am sure the seller is not motivated to sell or need the money for bills.
The ironic twist to it all - in my mind is... at a $500 obo price point, you are basically valuing an original real cabinet at the same price point as an Arcade 1up. We know nothing beats a real cabinet! Also the balancing act here of "My games have no value, its a hobby" when it comes to buying... but when it comes to selling, people ask "how to go about maximizing value" and those threads are entertained as well. Are we here for preservation, for education, for supporting others, or to scavenge for deals. At first impression the OP has been a member of KLOV for 4 years, but not real active. They could be basing things on 4 yr old pricing. If we are all beating "This is a community, we are here to help in this hobby" drum, then isn't educating about various price points and markets part of that?
Maybe with that in mind, the seller could stick with the original price point, but make it truly Or Best Offer. $500 is the starting point, and go up from there.
It HAS to be worth more than an Arcade 1up, wouldn't you agree?