Dave Miller and mdugger,
Technology bashers not commenting?
Yes, we KNOW that fitness, strength and nutrition are understood and utilised so much better than in the past.
BUT....
....when I hit a small ball from the early 80s, or any other outdated ball for that matter, and then in the same moment, grab a modern ball from my bag and hit it between 15 and 30 yards further, and then 25 to 45 yards further than hitting the older balls with an early 80s wooden driver, I do so with precisely the SAME fitness, strength and nutrition that I hit the old stuff with 60 seconds earlier.
A longish par 4 on my old home course is driver, 4 wood / 3-4 iron with my good condition old equipment and near mint condition old balls (nowadays I can even get home in two in winter now I've grown up), whereas I hit 3 wood 8 iron / 9 iron with my war bird, Cleveland irons and Pro V1.
Enough of the argument that golfers' conditioning is the main reason. It is a factor, but technology is moreso. Try the comparison, like I have on numerous occasions.