Rear brake options

I wonder how magnummopar qualifies this better braking. He sells a rear disk kit so has a vested interest in such claims. I miss the engineering theory behind it. If the brakes can skid the tires how could any brakes stop any faster? Drums main deficiency is in not cooling off as fast, but rears need 1/3 the cooling of fronts. The other issue is unequal L & R braking, but that is more a problem from poor maintenance (oil on shoes, etc). Tires stop a car. Today's tires are much better than the bias ply tires of the 1960's, so don't rely on the stopping distance spec's from then. Most factory rear disks have mini-drum shoes inside the rotor hat for the parking brakes. Hard to see how those little guys are as good as much larger drum shoes. Probably fine for park lock, but less so for emergency stopping.