But by replacing Tonto's race you're taking a group of people who are a huge minority and saying they're worth even less and having a white man play them.
"Huge" minority? The 2010 census lists Native Americans as being less than 1% of the US population.
They're an even smaller minority by global standards. Hollywood thinks about the global, not just American, audience when making blockbuster type movies. Typically, the domestic/international split hits around 50/50, with some movies, especially the action-heavy and and kids' movies, skewing way to the international side. Throw a huge international star like Depp into the equation, and you'll typically see a stronger international skew even if the movie isn't action centric like
Transformers or specifically for kids.
That means over half the potential audience for the movie won't even be familiar with who Tonto is supposed to be (even if we assume 100% of the American audience is familiar with a character from a TV show decades ago, which is a rash assumption). So whoever is in the movie, that guy will be Tonto to them.
I wouldn't be surprised if number of Johnny Depp fans globally is greater than the total number of Native Americans in the whole world. The guy is a serious force in the movie biz.
And I wouldn't fret about the subject matter (Western) driving away the foreign audience. People worried about
Captain America too and last time I checked it was 54/46, with the international BO still trailing behind domestic. Subject matter is not a particularly important concern compared with factors like the amount of action and bankable names.
As for
Superman, I've no doubt that Will Smith (another very bankable name internationally) in the lead role would do much stronger box office than Henry Cavill, who may look the part but has no box office clout. Worrying about the race of an actor is completely beside the point. Check boxofficemojo to see the real story.
As for
Batman, Vin Diesel has proven his international bankability in the
Fast & Furious franchise (last movie: 43/57). Diesel as
Batman? Why not?
When it comes to decisions about what movie to go see, identities like "I am a Johnny Depp fan" or "I am a Will Smith" fan can be
more important than ethnic or racial identity. It's important to realize that race and ethnicity are just two of a myriad of factors that people use to sort themselves into groups, and that sorting can have a strong influence on their behavior.