I read that studios have to earn 2 to 2.5 times the budget to break even due to marketing costs, and splitting profits with theaters.
Just an example of their accounting tricks (my brother-in-law worked in the accounting dept. at Tri Star): If a movie has a chase scene and a parked car is hit, that is a write off for the cost of that car. Later another parked car is to be hit. They take the same car, turn it around, paint it a different color and boom: second write off is obtained.
Small tricks like that are legal and plentiful in the industry.