Those Haswel and DC chips would be worth a lot less than they would have been post Zen, as for Ivy and Sandy's, i don't think those owners care much given how long they have had them, they would probably be glad to get an actual upgrade in their price range.
And those 6800K and 6900K owners..... well they can probably afford to lose a few 100 more anyway, i doubt they care much, they will just wait for the 7900K and gladly pay £1000 for that.
I have a 4690K, did someone offer a soggy bag of chips and an out of date jogurt for it? what flavour is the jogurt?