I agree with the OP.
Not to mention, I think a good chunk of this is an awareness issue. Everyone keeps talking about the whole thing working out and things reaching a equilibrium but that takes people caring and paying attention to the value of a item which the price history is available but no one uses it.
A return to Xi's system actually enforces the perceived value of an item. When you look up an item to sell, there's no way to tell the real value. You get high amounts and really low amounts. Most people like laugh at the guy selling the item 2k more than everyone else but maybe he was on point and actually received buyers before the wave of undercutters rolled in effectively destroying that price point. No one knows he made sales at that price immediately either. They just know the last few people people went in a 500 less. Another person when in 1000 less. And the only real constant? You either sell your junk at that price or lower or GTFO.
The real value of the item diminishes and never returns because all the new sellers that are now fighting at 50% the original value feel reinforced by their prices simply because it sold quickly and they got cash. There's no reason for the buyers not to have a field day with it either. Now the peeps who were buying the item at 4k-ish regularly are like.."Sweet" and that's the end of it. Let's say the buyer wanted to be crazy and help stablize the price they can't. They could attempt flipping the item but that'd only be reasonable in certain situations (less suppliers and few stacks of the item). If they wanted to be a Good Guy and simply bought from the seller that had the item at the appropriate price it doesn't show the rest of the community that the item is worth that amount. It disappears and we'd assume he bailed or caved in to the undercutting. If it's still there, everyone wonders what's wrong with him.
It's in this case XI's system would thrive better. We'd know the most an item sold for and how well it sold at that price. We'd see the last time an item sold for a stupid high price and how long it's been sitting on the shelf since. When people go to sell they'd get to see how much they -could- be making on the items and not immediately looking at the bottom line to undercut it because they know if they didn't, it would never sell otherwise. Consistent prices showing up would create the equilibrium range everyone is talking about because sellers would know from X amount to Y amount this item always sells. Undercutters who went too low get to pat themselves on the back when they noticed they're the only ones who got paid half the value on an item. Most forms of undercutting would be masked by those who have grown used to the price range gap and always spend that amount. While promoting to the undercutter that went 1k lower that the value of the item is still the already common price range.
Right now, it's some horrible reverse ebay style bidding and it's horrid.