That's a good point though, and I do mention it in the book. I talk about how when promoting people it's good to define a 30-60-90 day plan (although there are many similar frameworks) and bake in a "no bad feelings" back-out clause if they don't enjoy doing that particular job. We've had that happen at our company numerous times.
Additionally, in the later chapter on defining management and individual contributor tracks, it does talk about levelling them in a such a way that allows mobility back and forth. People shouldn't get stuck going through the one-way management door. It's perfectly fine to go back (even though it's not really "back", it's just "across").