No one sells $4 lunch bowls in the US because no one wants to work for minimum wage for 12 hours a day. The article makes it seem like a great idea, but people in Japan who run these stores work like dogs and live in poverty for their whole lives.
Anyway, the main issue here is population density, not labor availability. If there tens or hundreds of thousands of people working and living in a quarter mile radius and average foot traffic was in hundreds or thousands per hour rather than dozens or less it would likely be easy to sell $4 bowls and make a profit - most of the US is vastly less dense and walkable than that though, even in cities.