AJ,
Swing speeds (some swing speeds, a few) are above 120 mph right now. These are not the long drive champs, but 'players' as I understand. When others learn the technique or teachers can teach the technique or enough kids pick up a driver and swing (as the USGA hopes and is trying to accomplish), then PGA norm swing speeds are likely to go up. There is some 'cushion' between PGA norm and test swing speed.
What if the 'future set' of professionals can learn how to swing harder and control the ball ?
Optimizing spin rates by modifying shell and core materials and shell and core dimensions is ... part of the ball, part of technology improving ball flight, and the game. There is a recent quote (unscientific as such) from Kenny Perry to the effect of golfball improvements.
You are right that straight is part of the game. Isn't that a ball improvement, getting the spin rate tuned in ? Doesn't the USGA set a spin rate to get the ball to go 'further'. Are spin rate improvements maxed out, in combination with swing speeds, at the same point in time ?
I have some golf balls in my garage that could again be manufactured for everyone and all......or, a redo as a tournament ball. However, when remanufactured, the spin rate might not be right for some players game and may not go as far.
Maybe you are right.... the toothpaste is out and there is no way to go back.
But, I think there is more to squeezed out of the clubhead, the golfball, the shaft, and players' ability, more than just a little bit and enough to force longer, more expensive courses and more rounds of renovations.
The experts say NO. Distance is now fixed.
The golf ball can be one way to offset distance. Limiting the clubhead size, COR, or length of the shaft will not cripple the game. Limiting grooves did not cripple the game (it cost a lot for some, had to grandfather some clubs, etc.)
Another way is to set new test standards, not above the swing speed of a few professionals, and monitor. It just doesn't seem like a long term plan to me.
So, I think there should be some plans. Plans would have to be to roll the ball back at some point. Do not roll it back now but be prepared to do it.