There's a little analogy to be had even at places like Amazon. Pick an item and take a moment to look at the sellers prices page, yes even amazon direct/prime, You can find pricing for the same item at three-fold for the same item on the supplier page. It's not rare, it's very common.
Domains like any market place are no different. A little look at dnjournal sales prices will show you the motivation behind high listing prices. One motivated buyer is all that is required, Everything cheap is down to how motivated is the seller, Do they need the cash flow or not. finding a distressed seller with a good portfolio was quite a common practice in the past - Not sure it works so well without 'Whois' these days.
Look at the domain make-ups that get sold on dnjornal then ask again, Many stun even an ol'hand like me. A lot of this weeks sales were particularly off-the-wall