What does it mean to “sell”?
When a work becomes widely known and loved for a long time, a “change” has occurred. The philosophical depth, social commentary, and complex inner lives of characters found in the original work are transformed into something more “understandable” and “approachable.”
For example, Moomin, GeGeGe no Kitaro, and Devilman. All of these have changed their forms from the original works but have become entities that transcend generations through anime and merchandise expansion.