I said economies aren't some kind of fair game. What matters at the end of the day, for players, is whether or not they have the gil they want out of it. People don't care what the most optimal way to get that is, only that they have it at the end of the day.
Whenever I've got something to sell I undercut for the quick sale and continue to ignore the marketboard until the next thing I can undercut. All I care about is that I get a decent enough chunk of gil out of it for the times I have to spend a quick 100k on one thing or another. I had enough gil to buy someone else a full set of Neo Ishgard armor, on top of the full set I already owned, when the average piece ranged anywhere from 150k to 300k a pop, and that's while barely getting involved into the marketboard economy at all.
Not to mention the fact any gil gained from the MB economy was farmed by other players to begin with. It's a valid way to make money, but not everyone is gonna give much of a damn about stabilizing it when most of us just need enough to get by to do what we need to do.