Hi! This is the Market Economics Fairy! I help supply and demand equilibrate everywhere! If there is unmet demand for a fairly easy-to-grow cash crop, then it means that the prices are too low! Raise them, and farmland will switch from other commodities as it becomes marginally profitable to do so!

Sincerely, the Market Economics Fairy!

(Full disclosure: I'm just borrowing this character because it's suddenly relevant.)

Same thing that happens when places get so crowded that nobody visits them anymore.