In my opinion the best way to learn cadence branking is to use a car that lacks the feature of abs. (Normally a car from mid-90's or older)
Take a wet road, a cardboard box (or similar to avoid damage), and a spot where there's no traffic and stuff to accidentally hit in case anything bad happens. Then speed up and try to stop as close to the box as possible, raising the speed each time to really learn what speed does with brake distance.

How I learned this technique is basically by not having ABS in my car (Volvo 440 2.0 '94) and as I tend to drive quite fast I've had some "training". The car is really lightweight, which makes it somewhat more difficult (in my opinion) to get any grip when braking on wet surfaces.

I think it's mostly a factor of panic or hesitation that prevents most drivers to not use the technique only because they want to stop as fast as they can. (Duh')