I've already seen my DC's entire stock of certain glam items get cleaned out by a single person then sold at a huge mark-up on multiple occasions.

There are tons of absurdly wealthy people (Often through less then legitmate methods) who are richer then they'll ever need to be and choose to flaunt their wealth by making the marketboard their plaything and it's rather aggravating.

Between them and the bot farmers (Which are frequently owned by them) the marketboard inevitably ends up degrading to a point where legitimate players have a really rough time making much money outside of selling really niche items that are outside of their notice.