Try as they might, some very high-quality fighters aren’t quite able to get over the hump and win a world title.
They’re excellent professionals who are often able to run the best in their respective weight classes very close but can’t quite beat them. A strong showing often leads to another opportunity, and so on.
One only needs to think back to Oba Carr in the 1990s. The Detroit native was an excellent amateur and was tabbed for future success as a professional.
However...