Snapnames, while obviously having a quality "drop" inventory, leverages human psychology (auctions, etc) and simple statistics to get top-dollar sales ... advertise a domain to many numerous potentially interested people with a good sales pitch, and it likely will sell ... and for top-dollar.
On a related topic, as quality domain names become more recognized by the public at-large as having real value, the valuations will continue to esculate ...
Think end-user, think real estate, think corporate ... 6-figures to many of us here seems like a lot of money for a domain, but in the eyes of investors, business, etc that's not much compared to what they spend elsewhere.
Quality domains, as perceived by an end-user, appear very rare ... I've observed, including on the forums here and in offers to me personally, that there are many people willing to pay 5-figures just to get "something decent" so as to get started / expand in the business ... that tells me that 6-figures will in the not too distant future become the "norm" for even decent quality domains.
Ron