I made an account just to respond to this and I think the thread is quite old at this point but anyway....
I think the reason you see pros hit it low is that they generally hit it 'pro-side thin'.
By that I mean their divots start about 4 inches after the ball. The average amateur who hits a 'good shot' tends to have the divot almost right at the ball. The amateur's 'good shot' angle of attack is steeper causing the ball to pop up faster and float. The pro's angle of attack is descending but shallower. This is also why the spin rate goes through the roof on their shots, btw.
Amateurs thin shots on the other hand tend to bottom out before the ball and then catch the ball on the upswing of the club.
Oh and so if you want to work on your game try practicing taking divots 4 inches or so after impact with your irons even your wedges. Also, be careful because when you do this the dreaded "s" tends to appear.