Just an observation, I think that the number of lessons is a far better metric than the number of hours. I suspect 30 to 40 lessons are typical for a private pilot candidate, and they probably last about 1.3 hours. If the length of the lessons are substantially longer, the airspace or the airport may be a factor. If the number of lessons is far greater, why? I suspect that it is typically because lessons are repeated - either because they student lacks confidence and wants more practice, or because a topic is challenging to the student and the instructor repeats the lesson until they "get it."
When I have students of another instructor, it is usually to focus on a topic they have trouble with. The feedback I often hear is that that correct procedure wasn't demonstrated to them enough. There is a tendency to have students fly the airplane as much as possible, which is good. But demonstrating things repeatedly can also have an impact on how quickly students learn. In my limited experience, practicing things that the student finds challenging results in a lot of practice for very little progress.