How important is race in comics? We're not even talking about skin color here, but American vs. Non-American. According to one comics editor, the answer is "very" - even if comics fans would rather it wasn't the case.
Responding to a fan question about the historic problem of comic series with non-American white male leads selling poorly, Marvel's Tom Brevoort wrote
I don't know that it's any one thing, but if I had to hazard a guess, I would say that it's all part of the same phenomenon that makes it more difficult to sell series with female leads, or African-American leads, or leads of any other particular cultural bent. Because we're an American company whose primary distribution is centered around America, the great majority of our existing audience seems to be white American males. So while within that demographic you'll find people who are interested in a wide assortment of characters of diverse ethnicities and backgrounds, whenever your leads are white American males, you've got a better chance of reaching more people overall.
Tom's syntax following that is a little blunt...man, I wish it were wrong, but it's not. Every comics publisher ever, including BOOM!, can tell you maddening tales of retailers who, even now, in the 21st century, are hesitant to order books with non-white, non-American leads because their community won't support them. It's absurd, it's crazy-making, I don't know what it's going to take to change that other than time...but like it or not, it is an unfortunate truth of the time in which we live.
Of course, now that Marvel will have the backing of Disney, who have had success with non-American, non-white and non-male leads (as well as recent accusations of racism all of their own), that might be about to change... if the audience will let it.