I would say they have little inherent overlap, but they are not mutually exclusive. A leader can cultivate both skill sets. I think the problem arises because as we advance in technical skills, it is an incremental advancement over years. However, switching to a leadership role brings on a large, deliberate, fast learning curve to pick up brand new skill sets. Many new leaders just keep learning incrementally, taking far too long to get good at their new role. But the ones who do make a fast jump, and actively pursue their missing skills, tend to be great people to work with.