TEPaul,
My point exactly! Likewise, they probably don't think there is any possible way a shaft could lead to substantional distance gains either, but I think its quite possible. Now I could be wrong but if the USGA wanted to try and limit this avenue before it ever became a problem they'd just need to specify a few rules about shafts:
1) minimum weight - lets say 45g because I don't recall ever seeing a driver shaft less than that, so how about 1g per inch of length
2) maximum amount of flex under some sort of test condition - pick what an Iron Byron test with the whippiest ladies flex shaft made today deflects, that's your limit
3) designed to bend the same amount regardless of orientation....OK, all but the very highest quality graphite shafts violate this to at least a small degree today, otherwise "spining" and "FLOing" shafts wouldn't exist, but they could just specify a lower boundary for how different the flex/frequency could be when measured along different axes
4) put some limits on the amount of difference in flex between different points along the shaft....i.e., now you can have "high flex", 'mid flex" and "low flex", though in reality the bend points differ by only a few inches today, and the difference in flexability between those points is quite small. They need to eliminate the possibility of shafts that are ultra stiff everywhere except for one (or more) spots where they are extremely flexible.
They ought to do this because trust me, you don't want to see what might happen when materials science advances to the point that you can have your swing tested in a manner similar to the TrueTemper ShaftLab of today, feed that data into a computer, and have a custom designed shaft that's of essentially infinite stiffness along every axis except the one your club will be moving along as it approaches impact, where you'll have one or more soft spots that allow the shaft to deflect 20-30".
I think its not impossible that they could engineer it to react properly with the way real people swing so it kicks right at impact. That'd be a bit tricky since on a full swing you reach your maximum acceleration and maximum clubhead speed before impact, but I think its a tractable engineering problem when you can custom tailor the shaft to the individual. The further from the ball you hit your maximum acceleration the more flex points you need to add some delay in the rebound...
Before anyone says "20 to 30 inches of lag, you are insane, no one could hit the ball!" you have to consider how much lag there is in today's shafts. I was measured with True Temper's ShaftLab with 7.2" of shaft deflection with the driver. That's on the high end of their range but isn't terribly uncommon. And while I'm not Tiger Woods in the consistency department (or a TEPaul, for that matter, I'm sure) I get sweet spot to meet ball more often than random chance would allow for
I think also with that much lag you'd feel what the clubhead is doing and be able to sort of adjust the rhythm of your swing to match it. Of course I could be wrong and maybe that'll never work, but do you REALLY want to risk that I might be right when it would be so easy to fix it today before the technology is developed?
And oh yeah, the fact they'll be able to make that shaft weight maybe 5g instead of the current 45g-85g range for graphite might also help the clubhead speed, and allow increasing club length even further if they want to, and that's true (and I guarantee you the technology to do that will be available in a couple decades at most) even if nothing else I'm talking about comes to pass.