Because if you sell an item on the ah currently you know how bad undercutting is, its a huge pain and it just lowers the cost way down because it goes like this. Sell 1: Item x for 20 g, seller 2: item x for 19g , seller 1 pulls item and sells it for 18.5, seller 3 comes in and sells it for 15, seller two pull his down to 14 seller one pulls his 14. But think of this with litterly 20k people at any given time trying to sell one item and undercutting non stop. Nothing will sell unless and bottom level prices. Making gold on the AH will be only to the botters where the time invested Really isn't invested so they will sell items for scrap.Why wouldn't that be healthy? The margins would be lower and the item on are lowering in price. People would need to create more volume, and the amount of transactions would increase because supply can easier meet demand. Only thing to be aware of is botting.
I use the number 20k because it seems realistic if it was ONE Global ah, with 10 million current subscribers.