The vast majority of athletes at Stanford aren’t pursuing professional sports careers, either. Obviously, some are, and a lot more than you would find at Harvard or Yale, but it’s still a small percentage of the athletes and a negligible percentage of the student body. Meanwhile, a friend’s child who went to Harvard as a recruited athlete in a sport where Harvard matters – this kid was and remains a potential Olympian – had just about as intense an athletic experience at Harvard as Stanford might have provided. The kid was an athlete first, no question about it. But got a great education, too, and friends who were not athletes, and really appreciated that.
Re: Economics majors at Chicago. The registrar’s page on the university website has links to quarterly reports with very detailed information about undergraduate majors. It’s generally true that 25% of the student body has economics as a major, but that includes second and third majors. (I think math and economics combinations are especially popular, in either order.) The IPEDs data you see on College Navigator and elsewhere only report first majors, so its easy to find contradictory information about the percentage of economics majors at Chicago vs. elsewhere.
Re: Demonic plans. I don’t believe anyone associated with the University of Chicago, including Jim Nondorf, have anything like @marlowe1 's “complete Princetonization” as a goal, or even think that would be a good idea. No one wants to mess with the rigor of the Chicago education or the intellectual quality of the university. I think they just want a more vibrant undergraduate culture, and to attract a broader range of really smart kids, including some who want to get really rich and name buildings at their alma mater.