i have no problems with people undercutting my prices. it's basic economics. as more people can make items the price is going to fall automatically. i have no problems selling my items. you have to learn to read the wards and if something gets cheaper than you can make an item then either move on or figure out how to produce the items cheaper. yes, your gil made does decrease, but anything is better than nothing.
to the people complaining about selling of out dated gear for cheap prices. if you buy a tv this year and decide to sell it when you get something nicer later do you try to get retail for it of just try to get it gone to get some of your money back? i personally throw it in the wards cheap and if it doesn't sell in a few weeks i npc it.