Comment by pengaru
He delivered that speech in 1986, so this would have been based on professional experience through the 60s-70s. A time before ubiquitous electronic communications. Back then you really would have been disconnecting by keeping your office door shut and focusing on your work.
Mapping those observations to today's environment, the individual in a closed private office is more like a hermit with a mailbox but no cell/internet connection.
I think that hermit now would be significantly more isolated than the closed door person, since no one else now is using physical mail for professional communication.