Looking at their menu recently I thought there was no reasonable way they could offer that much stuff. And if you look at it you're seeing the companies attempt to respond to a more health conscious market.
OK, fine.
But 1 of the tricks of the restaurant trade is to maximize the number of recipes with a minimalist number of ingredients. Currently, McDs does not do this. They've got salads and wraps and regular burgers and 1/4 lbs burgers and Angus burgers and swirly deserts with fruit and yogurts and ice cream and shakes and this and that.
Well, you're asking a minimum wage cook to act as if he's a sit-down restaurant cook. It's too many recipes requiring to much labor to assemble a single meal. Assuming he sticks around long enough to learn all that crap he's not going to stick around for the required ticket times for literally hundreds of people per hour.
I wouldn't.
When I managed a restaurant I had to teach cooks a 200+ item menu in less than 10 days. My trick for the burgers was:
"You know every burger gets a bun.
"They also get a PLOT.
"Pickles, Lettuce, Onion and Tomato...and it goes on the side.
"What does PLOT stand for?
"Good.
"Now the rest is printed on the ticket. So if it says 'bacon-cheddar burger' guess what goes on it?
"Good. Congratulations, you just learned to cook all 10 burger recipes."
McDs ignores this at their peril.