The limited number of wishes is crucial to the point of the story—two to make mistakes with, a third wish to undo them. The third wish returns the greedy characters to where they were at the outset, chastened by the terrifying experience of their wishes coming true. This kind of tale is another warning against greed, and against trying to change your station or the status quo. The best-known European variant is, of course, Midas and the Golden Touch.
[Cf. AT 775, Midas' Short-sighted Wish]