When you try and fail you learn a lot about what failure looks like, and that helps you identify failure modes in production etc. It is just ignorance to think you could become as effective from just reading docs.
Note, I am not saying that it is unwise to read docs, but you don't become wise by reading docs, you become wise by making mistakes. Wisdom isn't built by following wise advice.
I often find reading about 1/3 of docs / books is optimal. After that practical experience becomes more beneficial. Then when you encounter problems, search for specific information to resolve the issues most relevant to your goals.
Note, I am not saying that it is unwise to read docs, but you don't become wise by reading docs, you become wise by making mistakes. Wisdom isn't built by following wise advice.