Hi - speaking as an academic attending for well over 30 years, who tended to work more or less 80/20 over the decades (clinical time usually eats into academic time in this scenerio), I'd say this is a bit idealized and challenging to do for a whole career. There are relatively few 80/20 (or "triple threat") academics among young faculty anymore as getting and maintaining the type of funding needed for this is very difficult to do over a period of decades. As you move from a training grant to R01 and renewal, the grant writing process and promotion challenges get more not less frustrating, and, in my experience in hiring folks, etc, more tend to move out to greater clinical time (or admin) than to more research time. The work hours over a successful academic career are often less well-controlled in research than in clinical work, but it's variable.
So, 80/20 is a great option and is satisfying, but it is poorly paying compared even to pediatric full-time clinical care and very difficult to maintain currently over a career. Not an option for most right now unfortunately and I encourage those going down this pathway to be sure of their true commitment to a research career. It's awesome for some, but it's not going to be a common pathway for most or realistic.
@GoSpursGo might have some thoughts on this as well.