I feel like "useful" and "valued" are very poor terms for the situations described in the article. I think a much better explanation is that just because you may excel in one role (and be recognized as such) does not necessarily mean you'll excel in another role. And heck, I think it's important to recognize these qualities and limitations in yourself . Calling this being "useful" or "valued" puts an emotional/moral…
Some businesses structure this intentionally, to avoid the upward progression of salaries, and other businesses just arnt churning through projects and clients quick enough to expand to fit the upward momentum of their talent.
Recognizing the real constraints on your value to a business model is important to not get stuck in the backwash of business value.