I find the intention of not releasing all furniture recipies before the patch an interesting one as that will be what dictates the price of the market for the foreseeable future. As we do not know the required materials people cannot gather the materials in advance to avoid a massive inflation to the materials that are needed to make the most popular furniture.

As housing land prices gradually decrease the % of the playerbase able to own land to make a house increases allowing a steady market of furniture demand. But the cost of land is a huge tax on the economy further driving down the available gil players have to purchase with.

There is no fix to the economy or undercutting as almost every item is free (minus cost of repairing gear) with unlimited free supply the only real cost is time so items are essentially priced at how much people value their time used to gather the items compared to the standard demand/supply. With a still decent number of gatherer bots the time used to gather materials is almost 0 as nobody is actually playing the game and they can perpetually undercut the item down to almost nothing and then move to another item.