I’m guessing it’s mostly because I put less emphasis on them filling it out. When I started coaching, I got more information from new data than I do now, so I put more effort into getting as many people as possible to fill it out. Additionally, I got feedback that it seemed strange paying clients were spending so much time giving me feedback. So now, e.g., I haven’t been following up as much if people don’t fill it out, and the ask is probably easier to ignore.
Larger groups, coaching busier clients on average, and only asking at the end (instead of also after the first four calls) might also contribute.