Strangely enough, I came across that concept as a younger man (circa 1985) in a book The Films of Akira Kurosawa. In the commentary on Sanshiro Sugata (the titular hero is a judoka), the author, Donald Richie, lays out the thesis that Kurosawa villains were invariably "completed" persons. They are villains precisely because they have stopped growing. They might as well be dead. That insight strongly affected me then and now.
When we stop learning, we stay at an immature development stage of thoughts, feelings, and behaviors.
Perhaps eventually, we will see though the illusions of ignorance and learn/identify with more positive/healthy role models.
This requires an belief in the underlying goodness of humans and their natural progression towards wholeness, health, and happiness.
Thanks for reading, responding, and sharing space and time on the mat.