When I read the title I thought it was about tackling a different issue, I didn't even think what they've solved is an issue. The real problem whether a toilet is owned by a business or government is about cleanliness. If it's true like you say that Japanese toilets are clean then this is not a financial issue but a cultural/behavioral one. Here in London whether public, a coffee shop, or a pub/bar excpect to walk through pools of urine and perhaps even find some poo on the seat. Changing behavior is harder than changing a funding model. Related is how many people will have shoes on seats on a bus or leaving half a sandwich on the chair.