Although it is unfortunate, that the female lead is not asian, it all comes down to who people want to see and how much money the producers expect to make. According to Forbes.com, Scarlett Johansson was the highest grossing actor of 2016. The movies she was in earned the most money.
She is more popular than any male actor, asian actor etc. So it’s not really about whitewashing. It’s about making a movie while earning a big profit.