Why aren't there many drive-thru-only fast food restaurants? Isn't it more efficient and ergo profitable?
It takes a lot of maintenance and additional employees to keep a fast food restaurant running. It cuts costs to have only a kitchen and room for a cashier. Why not only have drive thru? I rarely see people sit in a fast food restaurant, anyway. If it's to attract people who don't have a car, then you can have a window for them instead of having a place for them to sit.