This is a very interesting question, I hope after we answer it you will have some data or have a great answer for it. I would have to say the group where the pros hit the long ball and the 80's golfers hit the short balls would win.
I hope this makes sense. I would like to find a teacher who, first, really focuses on what the student is actually physically capable of doing, and, two, respects the physical changes and limitations of the old golfer.
Last year, at 70, and after two years of taking golf seriously, again, I knew that I had fallen into bad ways of doing things. I paid an instructor (he has all the credentials) $600 for two series of lessons over the summer. He helped me a lot, BUT we hit a wall. He insisted that the only way was to hit with big muscles, never with arms, and with substantial side bend, like a baseball swing. Plus his ability o communicate to me was limited. I am in fair shape for an old guy and was able to incorporate some of this, of course. However, I will be finding another person. -Marv