I think that the prices are causing a panic, and that panic is raising prices, so, in effect, people are panic buying before items get out of their reach, which, in turn, raises prices even more. There is a very good way to stop the inflation - simply refuse to purchase the items for the amount specified.
Yes, I am just as shocked as you are with prices. But, for me, that means that instead of purchasing items for what I consider to be too much gil, I find other ways to obtain them.
Lets face it, if no one pays 20mil for a scorpion harness, the price will go down. If people refuse to pay the amount seen on auction or in bazaars, items will go down in price if the buyer really wishes to sell it.
Since prices are shooting up up up, I have seen so many people try to "cash in" on this phenomenon...this just causes the market to go up further. How many people do you know are selling their current equipment so they can make a profit on it while the prices are going up, banking on them lowering in the future? Or, how many people do you know that are buying endgame equipment for the NEXT job they are leveling that is currently lvl 30? Just stop stuff like that, and prices will go down. Remember, it takes 2 for a transaction. Just because someone offers to sell at a price doesn't mean you have to buy it.