Jeez, read the comments on this thread from /r/futurology. It's ridiculous how toxic they are.
http://www.reddit.com/r/futurology/comments/4kve3b/_/
More than half the thread is calling McD workers lazy and entitled and they can't wait for the robots to "not fuck their order up." A lot of comments are even saying that minimum wage is too much.
Yeah, I work with some lazy teenagers and whiny staff. That's a stereotype for a reason. But I also work with people who work hard and take pride in what they do. They put a lot of effort into keeping the store clean and operating smoothly.
I really don't think the job could be completely automated. Certainly some aspects could be.
Right now at locations with the kiosks you have to go to a cashier for any unusual orders, which they have to manually relay to the crew. The only way automaton could work is if they remove the ability to customize your order beyond some preset options.
Another problem is that if you've ever worked there you'll notice that every single machine is temperamental and likes to randomly break if you look at it wrong. Just in the last few months, our bun steamer has broken, our coffee machine has broken, our frappe machine keeps acting up, the grills have had temperature issues, a fry vat kept having "ignition failure" errors, a water hose got dislodged and started flooding the store and the walk in freezer had a leak and needed to be defrosted and cleaned.
I can't imagine adding a bunch of greasy robots with a lot of moving parts will do much to improve the situation.
Imagine that the Burger Flipper 3000 breaks during lunch rush. Imagine that the Wrap Master 2.0 gets a paper stuck in a gear or something and it throws off the calibration and it starts handing out 8 double cheeseburgers all loosely wrapped. Imagine that the Shake Mate springs a leak and only fills the cups halfway.
You're going to need operators and technicians on call. The machines are still going to need constant cleaning. At this point it's a factory job more than a fast food job.
Could it work? Yeah, of course. Fast food is a very repetitive process which machines are good at. But you lose a lot of flexibility and you lose the social aspect of it.
Despite what the comments in that thread are saying, most people like some human interaction when they order food. Especially seniors, and do you know how many old people go to McD's? If we automated my store we would probably lose serious money due to that aspect alone.