Keep in mind that the main purpose of ABS is to maintain steering control while braking not necessarily stopping shorter.
I agree. I have done quite a few tests in my RAV4 on snow covered roads.
NORMAL DRIVING
In normal driving I can stop in considerably shorter distances by using threshold braking compared to slamming on the brakes, and letting ABS bring me to a stop. For those not familiar with the term, Threshold Braking is applying the brakes at the highest pressure possible without actually causing a wheel to lock up.
(See Wiki Here).
PANIC BRAKING
When a child runs out from behind a snowbank, the instinct is to get on the brake pedal as fast and as hard as possible. This is almost certainly the reaction for an inexperienced driver, and is also very hard for an experienced driver to avoid even though he knows better.
Without ABS, all four wheels will lock up and you will continue traveling in exactly the same direction you were originally headed no matter how you move the steering wheel. If that was towards the child, well..........
With ABS you may not stop in a shorter distance, but you will vastly improve your chances to change the direction in which the vehicle was originally headed, and vastly increase the chance of avoiding the child.