It's too bad the auction didn't run it's course, but no surprising. Many large items or rare items get negotiated behind the scenes. Regardless of the ethics involved in ending an auction listing, it would be hard not to turn down a pile of cash being offered for these. Think about it, they don't pay ebay their fees or paypal their cut and they get all this storage space back!
Ebay is not all for the seller. Ebay hates to lose their percentage of the final value, something like 10%. Ebay also has mandated that sellers accept paypal on nearly everything. Paypal is very buyer friendly is listening to damage, incorrectly described item, etc complaints from buyers. If Paypal sides with the buyer, the funds are yanked out of your account. By the way, Ebay owns them.