Sometimes, in slippery conditions, you don't have any brakes, regardless of what system is installed on your vehicle.
Nods! Sometimes you have four tires, and sometimes you don't.
Another note about ABS
: It isn't neccesarily designed to bring your vehicle to a complete stop. One of its main functions is to keep your vehicle straight when you apply brakes - especially important when you are driving at speed.
Impacting an object straight on with the designed crumple zone is better than an irregular collision at a slightly lower speed.
Obviously the focus isn't on crashing your truck every time you hit the brakes in inclement weather...I'm just making an argument for why having ABS turned on at higher speeds is an intelligent choice.