The interesting problems do not respect your job title. They hide in the seams — the territory between fields, where the building physicist needs the cryptographer, where the marketer needs the roboticist. A problem that fell cleanly inside one discipline would already have been solved by that discipline; what remains is the joinery. The database that has to know what the building is doing; the robot the regulation never anticipated; the contract whose terms turn on chemistry no lawyer reads.
The trouble is structural. Specialisation staffs the fields and leaves the seams empty, because no one is hired to own the space between two job descriptions. The seams have no department, no budget line, no assigned expert. So they go unstaffed — which is precisely why The Generalist lives there. It is the native habitat, the ground the specialist cannot be assigned to, and the place The Bridge gets built.
See also: The Generalist Manifesto.