And even in movies where the special effects are min to nil, the movies are still very expesnive to make because the stars.get extremely high paychecks. Tom Cruise, for instance, has been paid over $100,000,000 per film.
https://en.m.wikipedia.org/wiki/List_of_highest-paid_film_actors
If I started a movie studio, I would only hire actors and actresses with very minimal experience to keep costs down.