@Chaqa: "Vote with your wallet, then. That's how the industry will take notice. Entertainment is an industry, and despite all the DiCaprios and Clooneys out there who are going to push to make things better, the bottom line is still king to the people financing the movies."
Said financiers are not wholly rational actors. They are frequently subject to conscious or unconscious biases on top of the biases of their audience. They are also frequently risk-averse, i.e., unwilling to reconsider biases that have worked out well enough for them so far. So a lot of stereotypes about what the market will bear are likely to persist well beyond their useful lifetime, and affect movie-making decisions all along the pipeline, with the effect of greatly reducing people's chances to vote with their wallets in the first place.
Responding to comments about diversity by saying that only "the bottom line" should dictate decisions sounds objective, but the logic of the bottom line is itself partially a construction of industry biases. So we do need the DiCaprios and Clooneys (and, perhaps more to the point, Lupitas and Spike Lees) who push to make things better--and voices from the audience as well--in order to counteract those biases.
(In any case, "So vote with your wallet" is sort of like responding to political advocacy with "So vote on election day." If you believe in the logic of the bottom line, then one good way to effect change is to persuade other people who are also part of the bottom line to your viewpoint.)