I do not know the American system but in France there are no places reserved in the "Grandes Ecoles" of Engineers or business schools. I am only the son of a very small salesman of bicycles, I always attended only public schools and thus free and I had friends of promotion whose parents belonged to all social classes, farmers, workers, employees, teachers, traders, engineers and entrepreneurs.
It is true that it was 50 years ago and that since the level of free public schools, primary and high school, has fallen a lot. Now the good schools are private and paying which creates a selection by the parents' money, but the entrance competitions are still open to all with no places reserved for anyone.