Not very common as a 'role', unless you're in the Navy. Because it's made up and it's an oddly specific description of some person the author observed. Everyone can become a 'deep diver' as appropriate. It's not a role, at best it's an archetype which evolves naturally if the organization allows for it. Nobody hires 'deep divers' (unless of course, we're talking about the Navy) or has a business need for 'deep divers'. All of this is just malarkey.