On: A Princeton PhD applied to 2,300 jobs and still can't get one

The graduate level understanding of multiple branches can be pretty hollowed out.

In practice you read the relevant papers, and have mentors and collaborators explain the insights useful for a particular purpose until you get the zeitgeist but not an in depth understanding of a neighboring field.

I wasn’t talking about altogether different fields, perhaps you meant branches of the same field in your last part?

Depends on how you want to define fields.

Fields that seem really close to the layman are surprisingly difficult to have any knowledge transfer.

For example Programming Languages and Compilers.