Since the golf swing is a skill, then perhaps the first question we would need to ask is how do we define practice.
www.freedictionary.com defines practice as "To do or perform (something) repeatedly in order to acquire or polish a skill."
If that is the case, then perhaps what we typically regard as practice must be wrong since most of our swings are inconsistent, even haphazard. One moment, we bottom the club out in front of the ball, the next we do it 3.78 inches behind the ball.
Therefore for practice to be practice, we need to be doing the same thing. What do you think the results would be if we spent half the amount of time we did hitting balls, practising in front of the mirror?