Horror movies are made on the cheap. No big bucks FX and one can hire no name actors. I think I read a study that horror movies have the best rate of return of any genre.
Horror is the home to some of the most business savvy and responsible producers and directors in the business. Everybody’s got a good handle on what their potential revenue is, how much that means their budget should be, and then bringing it in under budget. ROI is high because nobody’s eyes get bigger than they should be.