Americans can't be bothered to pay for a janitor. Airports are a near constant flow of people using the bathroom, and they are fine because it's someones job to regularly come in and clean the resulting mess.
Janitors can't do anything about graffiti. There's no graffiti in Japan like there is in America; it's a cultural difference. People there are trained from a very early age in school to not destroy or disfigure things needlessly. Americans aren't taught any such thing, because we think that parents should be the only ones to teach values, not schools.
