Earlier quoted context omitted.
"There are bold X, and old X, but no old, bold X." Replace X with any practitioners subject to sufficient risk as a result of their practice. I first heard it in the context of mushroom foraging.
The risks are highest when learners are at a beginner to intermediate stage. They know the basics, and have gained some confidence, but don't know enough to get themselves out of trouble. This is called Stage 1 in the Gordon Model of learning: unconscious incompetence.
Rather, there is a certain amount of objective risk in alpine environments, and the more time you put yourself in that environment, especially in locations you aren't familiar with, the greater the chance that something will eventually go wrong.
I'm always surprised by the number of famous alpinists who weren't killed on their progressive, headline-capturing attempts but rather on training attempts and lesser objectives.