Nor does your formulation explain the success of movies such as My Big Fat Greek Wedding (appeals only to Greeks?), The Blair Witch Project (no budget or stars), Slumdog Millionaire (even fewer Indian Americans than American Indians), or Fireproof (Christian box-office hit starring Kirk Cameron). Fact is, movies of any "demographic" can do well if they're well-made and well-supported. That includes Native-themed movies.
Indie films flourish
While major studios are looking for the next Star Wars or Titanic, here's how the market for "niche" movies is doing:
Specialty box office sizzlin'
Weekend one of the best ever for indies
The combined performance of a number of films delivered one of the best weekends ever for the specialty box office, led by the successful debuts of Warner Bros.' "Gran Torino," directed by and starring Clint Eastwood, and Miramax's Meryl Streep-Philip Seymour Hoffman starrer "Doubt."
Kate Winslet-Ralph Fiennes topliner "The Reader," from the Weinstein Co., also enjoyed a strong debut.
None of this, however, took away from holdovers Gus Van Sant's "Milk," Danny Boyle's "Slumdog Millionaire" or Ron Howard's "Frost/Nixon," all of which continued to do strong biz.
Fallacy of the big-name actor
If an actor has a following or a recognizable name in mainstream media...the marketing has already been done for the film. No heavy lifting, no having to sell a new face.
In The Lone Ranger (and Tonto), the title characters have the recognizable names. If this movie starred Toby Maguire or Elijah Wood and an equally unknown Native actor, it would have as much name recognition as the Spider-Man and Lord of the Rings franchises had. Fact is, with a big-name studio and director behind it, The Lone Ranger will sell itself no matter who plays the roles.
You could go down the line of comic book-style movies and disprove the need for a "big-name" actor. Brandon Routh as Superman. Christian Bale as Batman. Robert Downey Jr. as Iron Man. The ensemble casts of the X-Men movies. Gerard Butler as King Leonidas in 300. Box-office success simply doesn't require a movie star with past box-office success, a following, or name recognition.
Blame the financiers?
In short, you think the studios are willing to produce movies starring minorities but the investors are too racist to fund them? Given everything I've read and written on the myopia of Hollywood studios, I doubt it's that cut and dried. I doubt investors are much more prejudiced than studio execs are.
For more on the subject of how multiculturalism sells, see Reality Shows Reflect Reality.
Below: No-name actor Kirk Cameron in Fireproof (cost: $500,000; earnings: $33 million).