How is the "success" of the duke's and king's second advertised pla Twain's final jab at the town?

The Duke and Dauphin put on a ridiculous show. THey hype up their show overcharging the townspeople. The more money they pay, the better show, so they think, they will see. The townspeople's selfishness and vindictiveness cause them to not tell others that it's a waste of time. Rather, they play up the show so others will waste their hard earned money.