I think they did take a stab at removing items from circulation, in both the way some items get upgraded and the fact that items that are not in "Mint" condition can not be sold.
But here we are facing over saturation and this gets compounded every time any one throws up there hands and says "F it i'm out". How ever i do not think that adding a super hq teir is the way to go about this. Again its another market that will suffer the same exact fate. while it might help in the short term in the long run its just not sustainable in fact it could very well have very negative ramifications on the market as a whole.
Like others said the solution to this problem is to take items out of circulation with out starting the whole mess over again. Now what if instead of taking 8 items out of circulation to create one, you took the 8 items out and were rewarded for doing so by gaining guild marks or faction credits, anima, guardian's favor, or a whole host of other things. Yes i realise that is not a perfect solution either.