A Clayman,
The physics behind the golf swing haven't changed in 100 years, nor will they change in 1,000 years.
Mass X Velocity =
What has changed is the technology.
Swinging a solid wooden driver clubhead on the end of a 43-43.5 inch steel shaft could only propel a 1964 ball so far.
Adding length to the 43 inch steel shaft created more weight and the need for more strength to swing the club at the same or faster speeds. Most golfers didn't have the additional strength necessary to generate faster clubhead speeds with those clubs.
Try swinging a 50 inch driver with a steel shaft with a half a pound weight on the end, and tell me if you can get the clubhead speed to 50 mph. Then try for 30 mph.
The advent of lighter graphite shafts, and hollow titanium heads allowed for the reduction and redistribution of the weight of the club, and with titanium, with its greater strength to weight ratio, allowed for thin faced clubheads and faces, while retaining structural integrity.
These factors, lighter shafts, longer shafts, and head technology have allowed golfers to hit the ball longer, not fitness. At 61 I'm far less fit then I was at 31, yet hit the ball farther, despite the physical effects of aging.
How do you explain that ?
In addition, UNFIT, OLDER golfers are hitting the ball farther than FRANK STRANAHAN, a PGA TOUR PRO and one of the most fit golfers ever to play the game.
How do you explain that ?
You're either in the dark, in denial, or both.