Property management companies in the San Diego area are absolutely shit-awful and I've thought about starting a nation-wide property management company myself. There's just no way I could be any worse than what's out there.
I wonder what you'd need to charge? Lots of awful property mgmt companies out there because it cuts into property owner's profits to pay more for a better one. If demand is high, what's the motivation for the owner? I suspect they mostly go with the lowest bidder.