It's almost like Hollywood doesn't care. Weird.
Despite the complaints about 'affirmative action' and 'political correctness' every time a nonwhite actor is cast in a traditionally white role, movies are basically as white as they've always been. Researchers at the University of Southern California studied the 700 top-grossing films from 2007 to 2014, (excluding 2011) and found that there was barely a difference in the number of nonwhite roles.


"They're just casting the best person for the job" <--- no.
Hollywood is not even trying here. Casting directors don't even look at nonwhite actors for major roles despite the fact that most of them weren't explicitly written for a white actor. In fact, take the 2007 movie A Mighty Heart. Despite the fact that it was a true story about a nonwhite woman Angelina Jolie was cast in the role. This isn't about 'the best person for the job', this is about the fact that Hollywood casting directors are not even looking at nonwhite actors. If they were, our films might actually reflect current American demographics. But they don't:

And that's not even taking women into account.
"Only 30.2% of the 30,835 speaking characters evaluated were female across the 700 top‐grossing films from 2007 to 2014." (via). The US is currently about 40% minority and a little more than half women (via), and you'd never know it if you were going by our films. In American film, white men are absolutely the majority. They have bigger roles, more lines, and more parts. Which means fewer work opportunities for everyone else. And it means that nonwhite stories are 'other', they're not the norm. Stories featuring nonwhite characters are not seen as universal, they're seen as 'pandering', as 'politically correct'. But looking at the numbers, Hollywood is indeed pandering, but it's not to minorities.
"They're just worried about their profits" <--- also no.
Diverse casts deliver higher ratings, and a bigger box office return (via). Movies like Fantastic Four, with its 'controversial' casting of Michael B. Jordan as Johnny Storm are outliers. The Fast and the Furious franchise was hugely successful (competing neck and neck with the X-Men franchise). The assumption that whiteness and maleness are better for business is completely unfounded. "Movies with relatively high onscreen minority involvement (21-30%) posted $160.1 million in global box office receipts in 2011, while those with lower involvement (less than 10%) made just $68.5 million" (via).
So I guess Hollywood hates money?
Well fine. But in the meantime they're producing movie after movie that does an absolute disservice to us. Film and television, for better or worse, are part of our cultural identity. It's how we express who we are. Having positive representations of ourselves- ALL of ourselves- is necessary.