Tinker Agree, even though I think the idea of a longer shaft delivering a higher swing speed is overstated at times.
I was trying to get my dad to play a shorter, more lofted driver because at 83 years old he is still trying to hit a 46" driver with a 10 degree loft. I took a couple of drivers and my Swing Speed Radar out to the range with him to try making my point.
I had him swing his driver and the swing speed was 86 MPH (pretty good for an 83-year-old man). As usual, he suffered control issues, including this ugly, over the top pull-hook that he suffers from on occasion. I then gave him my wife's 42", 13 degree driver and it was like night and day. I'm not saying that all the problems went away, but he didn't hit one pull hook with it, and his carry distances were FAR better. The thing is, his swing speed only dropped to 82-83 MPH. I think that many people struggle with the longer shaft length and my dad's swing freed up a bit when he had the more manageable length.
Unfortunately, the male ego never dies, and I couldn't get dad to swing my wife's driver on the course (after all, it was purple and had a pink grip -- what if he friends saw him 🙂). So, I have built him a driver with a nice, light, blue shaft, at 43 3/4" and 12 degree loft. We'll see how that goes.