THe more one relies on book knowledge to the exclusion of real-world knowledge, the more of a "don't have a job" kinda person it is... unless it's in academia.
True "book knowledge" does not exclude "real world" knowledge. There is only ONE form of knowledge. If the book does not apply it is NOT knowledge. That is why Economics continually tests theory with data drawn from the real world. Theories which fail to explain that data are rejected.
Sometimes working in a particular situation does not allow one to see the General picture or the Whole. The latter is a specialized labor like the former.