The drop in the markets has nothing to do with housing.. I actually posted this in another thread, but will repost this here.

Prices are dropping for multiple reasons, people don't seem to understand.

Prices are dropping because the value of said item is becoming less needed. Vanya set's for example were the craze end of sept thru october, but now with the increase in myth tomes, the i80 gear in a pretty easy raid, Vanya set is becoming obsolete, so now the price of the item needs to drop to get people to spend/waste gil on it, AND the price of the materials need to drop so that someone can still make somekind of profit. Now with the increase in the amount of philo tomes we get, and the ease of getting darklight, i80 and myth items(basically 1 i90 piece a week and approx 1000 philo tomes just to max out your myth tomes equals 2 or 3 pieces of darklight a week) excess philo tomes are being created very quickly and being used to buy mats and sold, so this is increasing the supply of materials for product that is no longer in demand, which again decreases the price.

So now we are at a point in the game where the supply of items exceeds the demand of product which is why the economy is going down. There isn't less gil in circulation, just no reason to use it. And now it also get's easier and easier to get gil (again maxing your myth tomes a week using duty finder high level routlette only grants approx 35k, if you include the other 3 roulettes, once a day, grants an additional 60 to 70k a week) they need to create more gil sinks to take the gil out of the economy (anyone notice that allagan pieces don't seem to drop in dungeons anymore?)

Now the hot new item in game was furniture for housing, yet the flaw behind this is, a) the prices are too high for the free companies to purchase land yet, so crafters are making items that are not needed yet and devaluing them quickly due to the amount of people trying to make a profit on what should be a hot item. and b)most free companies don't need to go to the AH to buy the furniture, they turn to their members and say, "Who can craft the tonberry lamp for our free company house". So now when personal housing comes out in which these items would actually hold more value, they will be so overstocked that again, no money to really be made.

And lastly, another reason for the decline in the economy is because everyone can craft everything. At the beginning, product held more value because there were less people making it and the demand for the said product was needed, now that people have hit 50, geared up, done their 300/450 myth tome weekly allowance, they turned to crafting themselves, which added more competition and supply of the product, and as supply increase, demand decreased.

Next we could look at the market of pvp which should/could have been profitable, but again by the time pvp came in, too many people were able to make the products the would want/need to use during their pvp match, AND since their is no official ranking system, the items/pots are not as needed.

So when all is said and done, there is only one market to make money and people are turning to this market now which is again starting to make the supply far exceed the demand since again, this market has very little use in end game raiding.