Well, you never know.
School may be vital, no... it is
But it isn't everything.
I think the key is more about the passion a film-maker holds for the material, than how many hours he's spent in college courses.
Example: Academy Award winning Director Quentin Tarantino, the man responsible for Pulp Fiction
, Reservoir Dogs
, True Romance
, and Kill Bill
, never even attended film school.
His famous motto was once "I never went to school, I went to the movies."
Paul Anderson definitely had the passion, but he lacked the skills as a film-maker.
To be honest, I think he's a pretty good director, but a horrible writer.
His films that he had nothing to do with the script on, typically turned out pretty good.