Knowledge is yours as soon as you earn it. It is a thing that can only truly exist inside a person’s mind, any time you take knowledge outside of mind, it stops being knowledge and is now a representation of it. Representations of knowledge do not immediately become knowledge as soon as you impart them into a mind. Merely reading a book does not make you as knowledgeable as the author, in fact a book can only effectively convey a few key points.
Most conflate facts with knowledge. But facts only provide a fraction of the story. The rest of the story has to filled in. The word we generally use for this “thing that turns facts into knowledge” is understanding. The word philosophers use is justification. If you took a bunch of baseball cards, looked at the stats on the back, by themselves you won’t be able to understand the rules of baseball from them or what makes each of those stats important. In theory, understanding consists of a series of facts. In practice, facts always leave gaps.
The ability to easily and effectively fill in the gaps between facts to impart knowledge only can reside in mind. The baseball cards can’t answer questions you might have of them. You could maybe use Wikipedia or another Internet site to do that, many people manage to self-educate. But the difficulty remains for the next person that comes along wanting to learn. Even if you gathered all the relevant materials into a course to teach someone, that course is only as useful as the facts within it remain relevant.
A person, who can observe and keep track of a changing field, is the only true repository of knowledge.