By locking in actors’ salaries, Hollywood studios were able to control the cost of manufacturing their products. Indeed, virtually all their films made money. Since the average cost of producing a film in 1947, including all studio overhead, was only $732,000, and the average net receipts for a studio feature amounted to $1.6 million, filmmaking was a lucrative enterprise for studios.

Edward Jay Epstein, The Big Picture: The New Logic of Money and Power in Hollywood