“Would he be served better at U Chicago, MIT or Princeton?”
Your really splitting hairs when you ask which college is best for your son. As far as the education goes it simply won’t matter, all will be outstanding. I would visit all of the colleges you’re son is interested in and see which he is most comfortable with, barring that, research all of them including the economic professors and see if there is anything that really stands out to your son, which BTW will help with admissions.