Well yes, YC likes the "we met in college" and I see your point but it doesn't mean it's flawless. Stronger relationships? Yes, the only way? No. There is always a risk when it comes to startups. Just accepting that scenario only is stupid and misses a lot of potential out there.

If you believe that only a certain pattern can truly change the world you are mistaken. In fact, that is the crucial mistake every incubator is doing. True innovation almost always comes from unexpected places.