I could get Missouri today if I wanted. I have about 150k free XP and another 800k or more XP banked on elite ships.
It would require over 25,000 doubloons to convert the XP though, or about $100 US.
As probably the most desirable premium ship in the game, the price tag is not unreasonable I guess. (two and a half Atagos, approximately) Is that how most people obtain this ship though, or do most people actually manage to accumulate 750k free XP without converting? How many games would that take, even?