The debate of profitability/sustainability vs. quick growth is a never ending one. You are right about Flipkart. but taht still doesn't take anything away from what the Bansals have built...
Look at Flipkart from India. Valued at over $15Bn USD. They attended the IITs in India yet build a world class company :) So to answer your question, there are people who still make it big despite not having attended the Ivies!!