Those distance gains haven't carried over to this 62 year old amateur.......
I do recall following Jack Nicklaus when he played with that Golf Digest Contest Winner. He went on and on about how he hits a 4 iron further now (this was 2004) than in his prime, but even some of his people whispered that he liked to ignore the extra inch of shaft length and fewer degrees of loft that essentially made it a 2 iron.
This study is a bit different in that it compares actual driving distance from then and now, not comparative clubs. I know a few years ago I played La Costa with Steve Pate, and he was still only driving it 270-275. Granted, sea level and cloudy, but I don't think he picked up much distance.
It's also interesting that he picked 1990 to compare, which is just a few years before the intro of the Pro V 1, which is where the biggest jump comes from. John Daly was the first pro to average over 300 yards - and that was 1997.
Some other differences could be the harder fairways, as noted, easier course set up that encourages swinging for the fences, and my favorite, extreme club fitting which can really increase distance, especially roll. That seems to be where most of the gains come from now days.
Jeff,
It is more than "interesting" that 1990 was the year picked for the comparison. That was still very much the persimmon/balata era, and really predates much of the golf "boom" not only for equipment, but for more and better athletes playing the game.
The Titleist Professional came out in 1994, I believe. Titanium drivers became more or less standard around 1996. The ProV1 type golf ball comes along in 2000. Somewhere in the midst of all of THAT, Tiger Woods demonstrates that fitness matters, and that hitting the ball a long way is a big deal. Somewhere in the 200-2005 range, clubfitting goes to a new level with removable shafts and Trackman.
Every one of those things are critical to the process of hitting the ball farther, so a "study" that selects a few elite golfers that have stayed relatively active, fit, and competitive and compares their 1990 distances to their 2017 distances is sort of meaningless. We all know that there have been distance gains over the last 30 years. Selecting the subjects of a study AFTER the fact isn't the way research is done. For instance, I'm 65 now, and playing the same golf courses that I played in 1990; I can absolutely guarantee you that I'm NOT hitting the ball farther than I did when I was 38! How come I wasn't in this guy's "study"? Fake news!
What might be more interesting would be to take those same guys and compare their distances in five year increments to get a feel for which of the developments in equipment had the biggest impact on each player. Like everybody else on this board, I'd suspect that it would be the opportunity to hit a Pinnacle off the tee and a balata ball on the approach shot, but there is a synergy to all of this stuff even at that.