Extreme Market Board Undercutting is a Problem. Who ultimately benefits from this?

[DynnDiablos]

If so many people are willing to sell the item at so low of a price, there is an abundance of that item. It's just free market at play, happens at every game with an auction house, nothing strange about it. If there is an item with high demand you will make money with it. This can be seen with materia, the grade 8 materia sells really well but it has seen a natural reduction in prize as more people have gotten their hands on them from dungeons and what not.

Then I will continue to buy them all up and re-sell them at 300x the price. Also, I can understand with a popular item this happening. But what I've noticed is like 2-3 people will extremely undercut and then everyone just follows suit, which basically saps all value from the item.