I think an open source project’s licensing has a ying/yang relationship with its community.
There are a lot of worthy contributors who would stay away from a project if they don’t like the license. So this affects how fast and in what ways the community around a project grows.

Another way to think about it is that license is a necessary but not sufficient condition for a vibrant community.

Leadership is more important to manage how and when people leave. In other words, the itch to make it better makes them come to project, good leadership keeps them there.