Pat,
From the age of 13 until when I had children I was never worse than a 3 handicap. My friends were the same as we never gave or got strokes in any game we ever played. We played a wide open course where I could drive four of the par 4's in 1977 where I can't drive any now. We swung as hard as we could while remaining on balance, exactly as we do now.
There are two very clear reasons why I hit the ball further as a 17 year old in 1977 than I can now. One is that back then courses were not irrigated so the ball rolled much further than it does today off zoysia. Two, that was the year I set my high school record for the 400 meters which still stands today and will not be broken in my lifetime. (49.09) I need to go at least one month without fitting that tidbit into casual conversation.
JakaB,
I don't consider "roll" hitting it further.
When I reference distance I usually do so in the context of "carry"
At one of the holes at my club there was a creek that required a carry of 234-240, so roll out distance was irrelevant, carry was the critical factor
Ditto three other holes with Creeks cutting through the DZ.
So, do you carry the ball further today ?
Like John, I used to swing pretty damn hard back in the day, much more aggressively than I do now, but I carry the ball further today (even despite aging, back problems and swing issues costing me probably ~20 yards of carry in the past few years) than I did back then, and back then I carried the ball further than ANYBODY I ever played with. I played a couple times with a tour pro back in college who was not top 10 but among the longer drivers on tour and there were a couple times when I hit a good one and carried my drive past where his had rolled. I certainly didn't have the proper boring trajectory you wanted then, instead I hit it very high so I had little roll unless the fairways were very firm. The type of drives I hit were just waiting for modern technology to catch up to, I guess
The changes in modern equipment has done much more than make drives go further. They changed the desired trajectory from the old boring "pro" trajectory you wanted in the persimmon/balata days to a high flattening trajectory you want with today's Ti drivers and Pro V type balls. A greater portion of the today's driving distance is from carry than used to be the case, so if the average pro is hitting it 35 yards further today than in 1980, I'll bet he's carrying it 50 yards further.
This combination of more carry/less roll not only makes carry obstacles like fairway bunkers and doglegs less relevant, it also makes rough less relevant. The less roll you are losing by landing in the rough versus the fairway, the less of a difference there is between fairway and rough. Not that playing from the rough isn't more difficult, but if landing in the rough costs you 30 yards of roll it is a bigger penalty than if it costs you only 15 yards of roll. When you combine that with the way 460cc heads minimize the penalty for mishits, I'll bet John would agree with me that despite lacking the overly exuberant swing speed of youth, a 450 yard par 4 that used to be a truly stern test back then is almost a joke today (by "a joke" I don't mean I birdie and par it every time, I mean I can heel an ugly drive in the rough and the green is still reachable, whereas back then doing that turned it into an instant par 5)