For the VMC 81, your also paying More money just for the Rarity Factor... , and again, remember a machine is only worth what the highest bidder or buyer is willing to pay. Also , some will pay more for a nice original rare machine as well, such as in this case..
I bought my 7up VMC 81 for 3000 and it's complete but needs total restoration, I've heard of some selling for 3-4, so it's a supply and demand type of thing. Same goes for Coke 81's which are readily available. you can pick one up for 1500 or less these days complete, Full restorations on a complete cooling machine run between $3,500- $4,000 from most reputable restorers and I'll include myself in that group (shameless plug)
but I can still sell a fully restored Vendo 81 B or D for $6000 range, and those people are buying them as they don't have the time, energy or desire to go out and "Hunt" for one to send me to restore.. they just want one..
Hope this makes some sense... but in realty, does any of this make sense... thousands of dollars for a 50 year old Refridgerator.. .what are we all thinking!