I feel for ya Rich, that really sucks. While I congratulate all the winners on some great deals, it is painful seeing such awesome books go for far below FMV. I have to empathize with the sellers here, while rejoicing with the winners.
As Bronty said, I too think this is a one-off event. I would have normally been in there helping to push some of these bids up but I only watched many of these as they were not current holes in my sets (upgrades of course but not holes), my focus was on some other books like those sweet Weird Fantasy's, and very tight budget right now after picking up a big win recently from CC.
I am not so sure about auction fatigue as even though they may get tiring at times, if I have that hole that needs filling I will typically go for what I need regardless. I think the multi-copies and presence of those high grade copies took the focus away from these books. If those HG books were not there things would have looked a lot differently I am sure.