Waiters and waitresses don't make $15 an hour! They make minimum wage (fast food workers make above minimum wage, if only by a couple bucks!) and the rest of what they earn is in tips. More than that - the government also decides how much tip money they earn a year, and tax them on it, regardless of if they got any tips at all!
In any event - I've worked at a McDonalds, and a Wendy's in the long past, and it's a horrible job. Cooks standing over hot grills, putting together all kinds of food, counter reps having to deal with rude people, etc., it's rough. So they deserve $15 an hour. Hell, they deserve $30 an hour!
But employers can't pay them that! Who is going to stop into a fast food restaurant if they have to pay as much for food as at a real restaurant? I can barely afford it now - went into a Wendy's yesterday and spent $5 on a chicken mozarella sandwich... that's maybe a once a month splurge for me.
It's not like these folks aren't well-compensated for the job that they actually do. I mean, they have to have a good memory to remember how to make each of the sandwiches or whatever, they have to be able to work under stress when the lunch rush comes, and the counter reps need to know simple addition and subtraction and how to work a cash register.
That is stuff that requires intelligent folk...but no special knowledge. Such workers are a dime a dozen. (Or they would be if people weren't paid more on welfare than to work at a fast food place...)
When I worked there...30 years ago now, we got half-price food, and a couple of dollars over minimum wage. I'm sure that hasn't changed. I think people who worked 30 hours or more also had profit sharing...maybe that was 40 hours...but really, considering how hard it is to find people who will work at fast food restaurants these days - again, standing over a hot grill or dealing with an impatient public - I would think they'd love to give people 40 hours if they'd show up on time, be clean, and do a good job.