It has been awhile since they have re-evaluated the landscape.
About 10 years ago, I called the USGA and spoke with the head of their course rating department. My inquiry was about their definition of a "Scratch Golfer". I asked if they had any plans to update their definition to properly reflect the length that scratch players generally hit the ball.
As well as the yardages that determine a par 3,4,5. 1956! was last update
"Par 3 - Up to 250 yards
Par 4 - 251 to 470 yards
Par 5 - 471 yards to 690 yards
Par 6 - 691 yards or more"
Their definition hasn't changed in these past 60 years on either account. Yet at the same time every male USGA event plays par 4's over 470 ( maybe not the Junior, but certainly, Us Mid, US AM and what I played in this week US 4 ball, in fact usually over 500 yard par 4's.
"Scratch Golfer: A male scratch golfer is a player who can play to a Course Handicap of zero on any and all rated golf courses. A male scratch golfer, for rating purposes, can hit tee shots an average of 250 yards and can reach a 470-yard hole in two shots."
This directly effects par, course ratings and handicaps. Obviously, these numbers are really old and not very effective which is why you have so many Plus handicap players all over the country. It makes those players playing in handicap events have a disadvantage in two man competitions when they have to "add back" strokes on 1 or sometimes 4 or 5 holes.
BTW, I was told that I didn't know what I was talking about in regards to Scratch Golfers, the reason it hasn't changed is because courses get rated every 10 years unless significant changes are made and they can't figure out how to implement 2 ratings for 10 years until all courses are rated and then simply switch over.