Too often do people think of working in a restaurant as unskilled labor that can be performed by anyone, which is partially true, however it is not complete truth. Most people haven't taken the time to look at it from another perspective or they haven't worked in a restaurant to really understand.
Yes, it is true that anyone can work in a restaurant (high school kids, retirees, felons, college students, single mothers, drug dealers, me, etc.) and no formal education is required for most restaurants to hire someone (unlike doctors, teachers, lawyers, etc.).
No, it is not true that anyone can work in a restaurant. Some people simply cannot hack it. Many people know they just cannot interact with customers, some people cannot deal with the nonsense that goes on in the kitchen, some people are threatened by the enviornment - a restaurant has far different work place culture than that accounting firm you interned at. There are at least two people in the world: Those who can work in restaurants and those who cannot.
Furthermore, it takes someone who can work in a restaurant to put in time to learn to actually build some real skills in the kitchen or in the front-of-house:
Cook = Unskilled labor
Chef = Skilled labor
Restaurants have such high turn-over rates for reasons more than just lacking salaries, it's a select breed of people that can manage to keep their job and sanity while working in a hectic restaurant.