Donuts are considered one of the favorite snacks of all time. People would prefer to buy a donut because it is cheaper compared to other snacks. Donuts can get one of the highest profit margins when it comes to the mark-up food.
In the early 1800’s Tokyo, street food cart is the first place sushi was sold. Sushi started being a street food for the working class and late-night the drinking crowd that they can eat all day. So the sushi food cart has a long history actually.