I met a kind of local (an hour drive) guy through social media and went and had a play date today. He had been introduced to the split tail previously and had never experienced an e2e system.
He has seen some modern gear at the climb store but not played with it.
Before I left, he cut a tail off of his shorter climb line and I gave him a climbing helmet, a carabinier for the split tail, and a brass snap on a little loop for a hitch tender.
Whatever the number of climbers on a closed system happens to be, I know that it is too high. This particular guy usually works around people who would have no way to get his rope back to him if he dropped it while trying to advance. The split tail is the single most important advancement in production tree work. Reach out. Encourage advancement. One climber and one step at a time is the only way that it will happen.
Edit: For the record, I was trying very hard to not be snooty. It requires doing. These climbers face the same risks that the more "with the times" climbers do. They're just a couple of years of education and practice away from where we are. It is more important to get them to be safer and more efficient than it is to show off how amazing you can be. There are very few competitive climbers who can't spare enough time and gear essentials to get another human really excited at least once a year.
He was one of the more receptive ones, but I've got a carabinier and four feet of rope even for the ones that are too cool to learn.