In most film schools and film production colleges the art of filmmaking is taught with the idea in mind that you will have a big studio budget to back your film.
Unfortunately, most people graduate and find that the big studios have no interest in their films and so they are forced to learn things about how to make a movie that they were never taught in film schools. They find that most independent films are created with a shoestring budget, and they are not connected to any major film studios.
If you really want to know how to make a film with a low budget then you need to educate yourself on the process of low budget filmmaking. The best way to do this is to learn from those who have been there, done that.