Well of course, it will be cheap if the item is undesirable.
Since pretty much ever? Stats have a pretty heavy effect on how much things cost, as do crafting materials.
Which is why I sold a Hauberk+1 for 40mil back when Osode was over 70mil? Remember when Blazn bought an Osode for 99,999,999G?
Stats don't have a heavy effect, it is a very small variable.
Means of obtaining the item, albeit the difficulty and rarity of the monsters it drops from and the HQ rate; these variables have a much heavier effect which reflect the price.
Osode is much more common than it used to be, especially since RMT have spammed Kirin. Use your head. Osode is much easier to obtain than HQing a Haubergeon. It's a common drop.
Over time, you'll notice Osode will continue to drop in price. The means of obtaining it are rare to fluctuate when RMT are farming it. They'll continue to drive the price lower, among other people who switch to alternatives like Haubergeon+1. Hell, even Kurei's LS would sell their Osodes because no one really needed it.
Damascus ingots are obtainable from a wide variety of methods and all of them do not commonly drop it. On top of that, it's rare to HQ it. Eventually Haubergeon+1 and Hauberk+1 will both be a lot more expensive than the Osode.
Look at this way. If Haubergeon+1 were easy to HQ and the materials were common, it would be a lot cheaper than the Osode. Take the scorpion harness for example. I've seen one damascus ingot drop from ODS and countless venomous claws. Claws are also widely available and P.body is a substitute for melee who don't need evasion, hence the current crash.