That's not how the model in the article works. It looks for high coffee, low fried chicken, because neighborhoods with fried chicken are already lost to the plebs. Low cost is explicitly checked for.

It does not predict a rise in chicken with value. Quite the opposite.

You're right, it is a joke. And it may not have been a conscious racist choice of fast food chain, but it could have been a conscious non-racist choice of fast food chain.