You lost me with your analogy. Let me extend the pigskin thought exprement a bit.
If I own the football team, and the field, and the city (hell, why not), then sure I can choose who plays QB, so I choose my son. Maybe at the start he's even not that bad of a QB, and our team wins some games. Everyone is happy.
After a little while though, people realize there's no sense trying out for QB on my team. My son, now left without anyone gunning for his job becomes complacent. We start losing games more and more.
With enough control over the market (like Apple has with the App Store), there become less and less QBs to choose from, and it's not just my team that gets worse, but the whole league.