Not sure what your point is here. Auction items go for whatever someone is willing to pay. So what?
I also see no point in keeping SoKs, you yourself admit you'll never be able to use in inventory, when you can sell them to get all the trade coins and gemstones you'd need to purchase the 8 Art Exhibition selection kits you'd need to build one. Knowing this, you have no one to blame for your lack of trade coins and gemstones, but yourself.
As far as possibly taking months to accumulate enough kits for a level 8, your lack of patience has no bearing on the value of the building. Besides, how long would it take for you to purchase and/or bid and acquire 8 Sunken Treasures or 8 Sleigh Builders?
Much ado about nothing
Yes, they go for whatever prize, which doesn't make it any more reasonable.
I have all the coins and gems needed for a fully leveled building right now and I blame noone for nothing.
And I have all the ST and SB I need, some of them also accumulating dust in inventory.
Actually, I need nothing that the AD can offer and that is why I don't sell items anymore. For me there is no difference, whether I store unused items or unused coins and gems.
I just shared an opinion, that these buildings, although very good right now, will probably be outdated by the time one gets enough of them.
P.S. I don't see any particular reason why someone must feel obligated to fiercely defend everything, that is offered in the game, even when it is not that good at all (No offence meant).