I recall when I first started playing golf back in Yee Olde Dark Ages having it explained to me by my teaching pro that for the best players a par-3 meant one shot to the green plus 2 putts. That a par-4 meant two shots to the green and then 2 putts and that a par-5 was a hole which would need three full shots to get to the green and then 2 putts and would generally be played with a driver, a fairway wood and a short iron.
Let's see Dustin Johnson - driver 357, fairway wood (say) 310, short iron/full wedge (say) 150 that's an 817 yard hole.
Let's take this a step further for an imaginary 18-hole pro-tour championship course.
Say 4 x par-5's at circa 800 yds each
Say 4 x par-3's at circa 200 yds each (about a mid/short iron for DJ)
Say 10 x par-4's at circa 600 yds each (a 357 DJ drive plus a mid iron)
Total length of imaginary par-72 18-hole pro-tour championship course = 10,000 yards.
The modern player isn't better, he's just longer, and that length is because the pro-tour at the highest level is now, with a few exceptions, largely full of athletically tuned-in fitness junkies who eat the correct foods, drink the right liquids, practice like hell, have great tuition from when they were kids, travel in ways that are less tiring, stay in better accommodation and get generally pampered. They are IMO not better players, not better ball strikers. They're just bigger and fitter and are better looked after and that combined with the new generation of balls, equipment and custom fitting means the pro-tour game, and probably the game for high level amateurs as well, is now a game 'none of us are familiar with'. It's gone crazy.
Rant over.
All the best.