Sometimes the most obvious solution is not the correct one. The courses HAVE been shortened...by technology. The ball/club combinations of today are nearly 10 pct longer than 10 years ago....so a 7500 yd course is like a 6750 yd course "back in the day". You can grow rough higher, pinch the fairways, etc, and what will happen? Tiger and VJ will still hit driver, because if they have a smaller chance of hitting the fairway, then at least they want a wedge in their hands. With a 25 yd wide fairway, they can still miss it with a 3 wood or a 2 iron, but then they have to dig an 8 iron out of the rough. Tiger said as much in pre-US Open interviews. He said he would hit drivers down there as far as he could, to at least get the wedge in hand.
The fact is that with 300 yd average drives and 150 yd pitching wedges, most courses on tour play Driver/Wedge, which IS boring to watch. However, shortening the courses doesn't help much here. The USGA (and the R&A fell asleep on the tech issue, and the only way to bring back shotmaking is via the dreaded "rollback".