Answer is money.
The best Kenyans are already making money on the world stage, so they're not coming over.
The next best Kenyans are being bought out by other countries.
So the 3rd level is what you'd get. After you filter out those who dream of making it big while training with the best, and then filter out those who won't leave for nationalistic reasons, you still have to sell these kids on the idea of coming to America. Most are part of a family, and taking an able-bodied worker who could help earn a wage, no matter how small, away from the family WITHOUT him (or her) sending back money is a tough sell.
But even if you get some people after that, the college still has to foot the bill. Does anybody know of a college that is currently paying (or willing to pay) tuition AND room & board AND textbook costs AND insurance AND all other college-related expenses for EVERY member of its cross-country team? 'cause that's what you're asking in your scenario, OP.