ABS does limit maximum braking effectiveness, but a driver would have to be extremely practiced with the vehicle and the road conditions to stop any faster. The main purpose of ABS is to keep the wheels turning, which maintains the ability to steer. Most people don't have the reaction to ease off the brakes while turning to avoid an obstacle. Traction control limits wheel-spin to provide greater traction. Static traction is greater than dynamic traction, and static traction is maintained only when the wheel is traveling at the same relative speed as the surface it's on. Both humans and computers can only tell how much traction is available by periodically testing it by spinning the tires, and then backing off to just below the point where tires spin. The difference is that computers are able to react to this test much quicker than a human and control power with greater precision. My Prius does not shut down power when a wheel slips; instead it reduces output. In fact, the Toyota is more generous in allowing wheel slip than my Acura. Most modern cars do not have limited-slip differentials or other means to transfer power to the wheel with the most grip. In fact, normal differentials transfer power to the wheel with the least traction.
I can not find one documented case where temporarily disengaging traction control to get out of a fix, or prevent getting stuck, has blown up a trans-axle. Anyone that has seen my post knows I am outright anal about taking care of my vehicles. You folks are over thinking this. Use snows, muds and chains when dictated and disable TC only when required.
