I am nearly sixty and have been flying for 27 years or so. There are certainly many ancient pilots around, and I agree that they tend to dominate the Club bar scene.
However, many people can only afford to learn to fly in middle age, and thus will always make up a large part of GA. When I and many of my ancient peers have hung up our headsets, there will be a further set of old cronies to follow along behind us, that's for sure...