I'm also a six-sigma black belt, so here's how I figure it: 30-45 seconds/unit processing (remove from freezer, queue, cook, pack, etc) plus 1:15-1:30 of non-processing (taking orders, cleaning floors, filling ketchup dispenser, unloading trucks, etc). Exclusive of managers etc, that gives me my 2 minute guess. It's probably a pretty good guess, because Mickey Dee's is already awfully efficient as a business. Wish that made the food better.
OK.
An increase in the minimum wage will affect less than 15% of all workers in America. There's no sign of that in the previous analyses. When you multiply the total labor cost like that, using the absolute worst-case scenario, it doesn't take into account the people that don't get a raise or the people that don't get much of one. That's a pretty big flaw.
Although all those employees don't make minimum wage, some would still be affected (all the $9/hr folks). That 67% labor increase number doesn't mean that ALL the labor costs increase 67%, just the 9% of people that make $7.25. There are some people that are going from $9 to $10/hr (11% or whatever) and many, many other people that aren't getting anything.
If you're using a high-level approach, A goodly portion of McD's labor costs are people like shift leaders and managers that won't get anything but a headache from the increase. Will managers get a 67% increase (eg $60k raised to 100k)? No way. Will I get one? Not a chance. At the store where I used to work (for me it's been like 15 years), it would probably affect 60% in some way, 40-50% of
those folks would have been minimum wage, and almost none would be full-time.
If it takes an hour (in total) for each burger, my McD's would have made (18 emp x 6 hours/emp) about 100 burgers a day in our 1000 ticket/day store that served maybe 1500-1700 burgers-or-whatever/day.
The numbers I used are the ones I actually use to plan my catering jobs, which are usually-but-not-always profitable. I usually expect 3 hours of loading and unloading and paperwork and prep and all that stuff to each hour of real cooking from my guys. I budget 25% of net for labor and 30% for food cost, plus 30% for overhead, and a little profit (simplified).
9% of the workforce is about 2.000.000 people and a majority of those folks are part time, and impoverished, making less than $10k/yr. Prices DO go up when wages go up, but it's nothing like the 1:1 correspondence that you're assuming.