You have a few different factors at work:
1. Many people are nervous buying a car sight unseen, especially on eBay where scams are not uncommon.
2. This is only the fourth thing the seller has sold this year, with the most recent showing a NEGATIVE feedback. Would you be comfortable dropping $65K+ with "NOT as described. seller will NOT return calls" as part of the latest feedback? No dis on the seller, just an observation.
3. There was only one bid: The starting bid was the Buy It Now price. In other words, the seller (a broker and not the owner) chose to liquidate the car in one day. Heck, it could have been a bank repo like the blue/white '97 GTS that sold for $34K last year. Is that indicative of the market? No. I sold a similar '03 with more miles not even two months ago for $69K. And had other offers after that.
One of the biggest problems you have with the SRT-10 market specifically is with dealers that have not sold Vipers before. They ask over sticker on the car while leaving it on the showroom for five months. It gets bumped and smeared by hundreds of people (kids, tire kickers, etc.) and doesn't sell. The more likely buyers don't return based on price and showroom abuse. The dealer then decides to dump the car just to get rid of it. Usually at invoice or less. This does not help the resale market at all, especially when you can still find an '03 on somebody's lot for less than invoice.
In the good ol' Gen I/II days, the cars would be almost exclusively distributed to Viper dealers that knew how to sell them (slight discount off of MSRP). They were also distributed based on pre-orders: Most Vipers had a "This Car Built Especially For..." on the window sticker, meaning they were sold before they arrived at the dealership. When I was at CAAP this past week, there were numerous '05's ready to be shipped - and not one was "Built Especially For..." anybody. That means they aren't sold and are destined for some remote dealer that will sit on it until they dump it at a loss. This could also mean that less buyers are ordering them and more are just shopping for leftover new cars. Also note that besides the Mamba cars, there are no options to be had on the SRT - no stripes, no interiors, no performance packages - nothing. So why order one to your specs when you can probably find some smaller dealer dumping the exact same car in a town near you?
I could go on, but I think I have digressed enough at this point...
PS. And nice car and great buy Bernie!