I think one of the reasons people quit is because they're afraid they won't be able to get better and better; that they have to come to a zenith of some kind.
In Hollywood, maybe only ten percent will make it and the other ninety percent try. This elusive dream of making it and being on top is the same story as the moth being drawn to the flame. The flame and it's attractiveness is something you'll never eliminate. Some will learn how to live in that environment and others will burn in it.
With today's fast films, you can light the way your eye sees the scene. You can abuse the film and create subtleties in contrast with light and exposure, diffusion and filters. That's what makes it an art.
The audience has to understand that if the film is going to have any meaning for them. If they are going to empathize with the characters, they have to visualize the process of concentration involved in making every move.