Your highest cost is labor. Now even more expensive. They will find a way to automate the process, cut down on labor costs and even more people will be out of a job.
It’s already starting to happen. Why bother with all the labor expenses when you can sell your product from a vending machine:
http://articles.latimes.com/2012/jun/13/nation/la-na-nn-pizza-vending-machines-20120613
IMHO, it’d be pretty easy to do this for hamburgers too.