I don't think you need to lengthen the golf courses at all. Maybe change the shape/architecture of the course a little bit. Maybe they could make the fairway from tee to green a different shape. Just take the fairways, say from 250 yards and in to the green and make it significantly narrower with a much tougher rough and more hazards for missed fairways. The tougher rough would start at the very edge of the fairway, not a gradual build up of the rough. If you want to go for it and you can hit it 315 yards, that is okay, but you need to hit it accurately 315 yards to be in the fairway or you pay a price.
This would make most of the players calculate more of the risk/reward than doing what they do now. The rough and hazards need to be really tough and could make it harder to hit GIR than hitting 2nd shot from say160 yard out.
Just a thought that would not require the lengthening of courses or altering the performance of equipment.
I'd like to believe that I play better walking, but I just don't think its true. I like to walk when I can, especially with my QOD, but my home course is really pretty hilly, and has some long green-to-tee walks. I'm pretty dang tired by the time I get done, and that shows. I don't have data to support it, but I believe I score better when I'm less fatigued, when I ride.
In this situation there is no one right there to ask, and if I'm not stopping for a drink/snack, I'm not bothered with even asking.
A secondary thought here is that, at least for me, whenever I ask anymore most people say no. Most slow players think they are keeping a good pace when they aren't. It is courteous to ask, but when the answer is no more than half the time and they aren't even around, I'm just going for it.
This all day...
Make the players choose to keep the driver in the bag because 330 yards out there is a bunker. Grow the rough. Stop cutting down trees; make angles important. Penalize inaccuracy
physics will stop distance gains; there is a limit to what is possible; so let’s stop with the sky is falling. Just change the decision making process