If everyone wore masks like they do in China and South Korea and Japan

Masks are a social politeness. They prevent carriers from spreading the virus by coughing or sneezing or touching their noses and mouths and then touching hand rails or other things. They don't really protect other people from coronavirus but if you are a carrier they prevent you from spreading the disease.

If you look at how South Korea and Japan have controlled the virus you see why we might need to be wearing masks here too. Otherwise, more people in any civilized nation may die here than anywhere else on earth. And that would be not only horrific but also embarrassing as a nation for that to happen.