Yes, that's all true. Passenger vehicles are generally designed to have enough power to lock the brakes as good design practice. FMVSS 105 requires passenger vehicles to stop in 215 feet, heavy trucks have a much longer distance. You'd have a hard time doing that if you didn't have the power to lock the wheels. Yes, I know it's more efficient to brake at the threshold, but if you don't have the power lock the brakes, you don't have the power to get to threshold, either.