This is one of the most revered of golf's hoary old traditions, most of which are extremely unsound, as indeed is this. One has undoubtedly a great tendency to come back to the ball by the same route as that which one uses to get to the top of the swing. It will, however, be apparent that if one goes back, as one is instructed to, well in a line with the ball for some inches and fairly, or perhaps I should say comparatively, slowly, and then returns at top-speed to the ball, as one must in order to drive well, one will return by the most direct route possible, which route one certainly did not take on the upward swing. This is another of those incorrect and unnecessary "axioms" that may with much advantage be forgotten.
There is one good point in this unsound "axiom." It may perhaps make the golfer strive both in the swing back and the downward swing to keep his club head travelling for as long a time as possible, or rather for as great a distance as convenient, both in the upward and downward swings, in the line to the hole produced through the ball. This is of importance.