Surely kids as brilliant as these ones sound are getting full scholarships to college?
If you really want to test the hypothesis: that university is not worth the cost for people like the Thiel fellows then I reckon you'd need two groups. One drops out of university and gets $100,000 and extensive mentoring. The other group stays in university and still gets $100,000 and extensive mentoring.
I see it's been a while since you went to college. Let me introduce you to a concept called "need-based aid:" it's virtually impossible to get a full-tuition scholarship at a top school based on academic achievement.
See also, market segmentation -- http://www.joelonsoftware.com/articles/CamelsandRubberDuckie...
I agree. It's not really a valid experiment, which is why I said "might plausibly be" instead of "is", just to acknowledge some connection with the education bubble debate. Though two things to keep in mind for a valid experiment are that from the 100K for the second group would have to be subtracted the costs of university over two years (for me [mostly my parents actually] that's more than 100K), and that at good universities at least extensive mentoring is readily accessible. So it's a reasonable approximation at least.