If you look at the reviews here at /r/ghost_in_the_shell, the vast majority of reviewers who liked the film explicitly mentioned not caring about whitewashing.

Considering Hollywood's traditional exclusion of Asian actors, it's unlikely that many people stayed away from the film because of its casting of Scarlett Johansson (Margot Robbie was the only other actress considered for the role).

Marketing probably wasn't the problem. Commercials and other media seemed to be highly visible. Most potential viewers didn't seem to notice the deceptive marketing about "unparalleled diversity" -- proven false when four out of five lead actors in the film turned out to be white (Kusanagi/"Killian", Batou, Kuze, Dr, Ouelet, and Cutter).

The continuing curse of anime adaptations seemed not to be a factor judging from the nearly rapturous, glowing reviews by some anime fans here at /r/ghost_in_the_shell.

Also, most Americans don't know the philosophy behind Ghost in the Shell, so they wouldn't know that the transhumanist ideas were dumbed-down and stripped away to leave behind a RoboCop-style action blockbuster.

Most viewers were probably unconcerned about Scarlett Johannson's diversionary claims that the film was "feminist" instead of racist. They probably were not swayed by her decision to blatantly lie that she "would never attempt to play a person of a different race", when the entire plot of GitS2017 revolved around that specific fact.

Although the story was a dumber mashup of Ghost in the Shell concepts, no one said that there were gaping plot holes or inconsistencies in Director Rupert Sanders' superficial "homages" to the source material.

The only consistent complaint that most people agreed on was that the dialogue was laughably bad in many places, but the visuals usually provided an effective distraction.

Most reviewers agreed that the visuals were beautiful, and Scarlett Johannsson's star power was considered to be almost beyond fallibility.

Given these factors, we saw Gits2017 overtaken by an animated film about a baby. Boss Baby earned $49 million in the United States alone, whereas GitS2017 earned $19 million, which is less than half the amount earned by Lucy in 2014.

So why did the film fail so badly at the American box office? Did the American public finally get fed up with whitewashing? Or did Sanders overestimate his ability to create a "new" Ghost in the Shell out of recycled old parts? Or did people notice Scarlett Johannson's obvious lies about "feminism" used to shift attention away from her choice to play Kusanagi Motoko? Or was it just not a good movie, despite the strangely fawning reviews posted to /r/ghost_in_the_shell?

Or..?