The whole point of taking over the net is to gain the advantage of hitting angled winners. If you're both playing on the baseline you have no way of returning an angled winner to the short T. Hitting from the baseline gives your opponents lots of time to react to your shot. At the USO Paes and Stepanek were able to win by playing smart doubles, constantly taking over the net in tandem, cutting off the angles to their opponents. The woman on the other hand, mostly played club doubles, one-up/one-back, cancelling each other out. The pro players with good volleys learned to volley through playing a lot of doubles coming to net.