That's only one model of learning a skill. There are many, many more.
The first time I put on a harness and spikes was to do a removal. The tree was in the open so there was no rigging. I had a good mentor/teacher right there to correct me as I worked my way up the tree. A close relationship between student/teacher works.
Over the years I trained many climbers. Most of them only climbed at work with me. Some would study videos or read materials I shared with them. Others did no out of work study.
Other climbers hired on who needed to be taught proper techniques. They were on their own to figure things out or learned from someone who didn't know the right way to climb.
There is a axiom of sorts in teaching that states that a student will only absorb 10% of what they are taught. In order to absorb the other 90% of what is in the lesson plan they need to study more.
Now, what happens if their teacher only knew 10% of what they needed?
Do the math...