Your logic about heat is still flawed. If the current flow is spread out more over 2/3 wires, then the one run will produce more heat, thus more resistance. You shot yourself in the foot. As for the motor and house comment, all electrical applications have a few very important factors that are shared in all applications.
There are way too many people who have ran CCA in high power applications and have had 0 problems. I won't deny that OFC is the best route, but sometimes the budget route is that much easier on the wallet and provides the same performance.