And the potential market for Bitcoin is as big as that of the major fiat currencies. That's quite a market that can be created, or more accurately - replaced.
Given that only 21 million coins will ever exist... If the bitcoin economy were to grow, the path to becoming a giant may not be to corner some market, but at whatever you do... acrue bitcoins over time.
It would only take around 2 million USD to purchase 1% of all the bitcoins that will exist. Of course if you tried to buy these all at once, the market would reflect your interest.
The idea that Pirate is selling coins to people wishing to acquire them without reflecting the market is certainly feasible.