As you know, in a fair auction where all bidders have the same information, the winner generally pays too much. In cognitive bias terms, this is called the “winner’s curse.”
There is also a cognitive bias called “anchoring” where the first party in a negotiation to mention a number tends to anchor the negotiation toward achieving that number. Auction estimates serve as a strong anchor towards a final price.
From this observer’s point of view, it was interesting that the bidders overcame the anchoring bias of the estimate. As the final price was so much lower than the low estimate, the buyer may feel they got a great deal, but they still may be a victim of the winner’s curse. Only time will tell.
Funny that Tarisio subtly (or maybe not so subtly) kind of rubbed it in Sotheby’s face that the price was so low relative to Sotheby’s estimate. That’s the second time in a year or so that a major art auction house has had a poor result selling a Strad relative to their estimates.