These mega budget films generally pay off from the studio's perspective. Many of the most expensive movies of all time are also the top grossing movies of all time. Even when an extravagant film fails to recoup costs in the United States, it generally makes a profit in the global market.
Avatar is the most expensive movie ever made, with $150 million spent on marketing and promotion alone. The biggest expenses were new film-making techniques and graphics as well as the creation of a new language that involved hiring a linguist.