Taking a contrarian viewpoint. Does the convergence of all talent into one team actually reduce the innovation in the startup ecosystem. Similar to your sports analogy, the best games result when multiple talented teams fight it out. If all startups that become big are YC-funded, then we might see just the YC-influenced style of running a company whereas other models may not see the light of the day.
But it's not competitive in the same way sports are. If you're a basketball team, you only succeed by beating other basketball teams. If you're an investor, beating other investors isn't the definition of your job. It might happen incidentally, but not by definition.
Funny that you make a sports analogy here. I wonder if the partners see themselves as players or coaches. After listening to Scott Kupor from a16z talk, I know that they see themselves as a talent agency rather than being directly involved in the "sport".