^^^Again, I'm not so sure what exactly is "obvious" here. In my way of thinking, they might have been very confident in their ability to make an incredible film, tell a great story, etc. It is less clear what impact they might have thought specific casting decisions had on their production. From what little I know of casting, it seems very likely they might have favored widely known stars versus unknowns to increase the likelihood that they could create buzz, interest, and/or revenues. There actually are fairly few Spanish actors that realistically fill that bill -- to be fair, if Penelope Cruz is contracted out on other projects, that's about it for preserving some accuracy in the casting, while shooting for maximized box office.
So you could go non-racist, i.e., cast whatever race star you can get for husband and wife and kids, but then you might end up with a somewhat confusing mix -- perhaps black dad, Asian mom, one white kid -- perhaps a Mayan descendant kid, and another that was not easily identifiable. Then you start to distract from your story and introduce complications in the imaginings of the audience. In that same way it would be a distraction to have the native population made up of 33% white, 33% black, 33% Hispanic -- that kind of thing is only going to induce head scratching. What is obvious to me at least, is that they went with undeniably racist casting choices, versus non-racist, which is to say simply concluding race just had absolutely no bearing or relevance on their project -- of course it did/does.
So, could be they couldn't get Penelope, then decided to preserve the racial homogeneity of the nuclear family (while converting it to white), or, as others have suggested, they converted to white because they in fact DID anticipate the racism of the moviegoing public and sought to avert relegating their film to instant obscurity by serving up to white audiences their comfortable white protagonists. Either way, I don't think they can be faulted for their calculus, racist as it was, because racism -- benign identification with racial and cultural commonality -- is just the way human minds are put together for better or worse, AND big money was at risk -- certainly wasn't my money, so who is to say what they did was wrongheaded?
Anyway, in my view those choices had little if anything to do with the film they ultimately got -- which, unless I miss my guess, is actually an attempt to flow against the grain of their racist choices -- it seeks to demonstrate the universality of human experience in the face of disaster, extreme challenge and hardship, no matter what specific subdivision of the human race you happen to be (...BUT, by the way, our featured folks are going to be very white, so you don't have to worry about that...)
Now as to where this production really went wrong, I was altogether unimpressed with the LFE in this movie -- while it was not MIA completely, it could have had some real memorable reference ferocity and impact. So while corporate decision making vis a vis cultural issues might stir some limited conjectural curiosity, I don't know that skimping on the LFE is the type of thing that can be so easily understood, much less forgiven -- that is miscalculation of the gravest variety in my book...