Periodized powerlifting training starts a cycle off with lower weight and higher reps to build a little muscle and gradually reverses this over 2 or 3 months to train the new muscle to increase one's 1 rep max. Whether doing classic periodization or not though, powerlifters know they need to build muscle, and that means higher reps, and they put that time in somewhere.
I used to do 5 sets of air squats to failure twice a week, and my legs got huge.