Technically thats not what happens. It doesn't shut down power. That would be like turning off your engine. The traction control is selectively applying the brakes to stop the spinning wheel, then should send power to the other drive wheel with the better traction. My car, not a Lexus, has the same feature and it does kind of suck. One second your trying to accelerate, then suddenly you come to a quick deceleration as the brakes apply. Best things to do are turning off the TRAC, like you stated, or ease off the accelerator pedal.