P.S.
"The goal was to create a reliable, distributed communication system that could continue operating even if parts of it were damaged by a nuclear attack."
This is a myth. The ARPANET was not hardened; quite the opposite. ARPA's goal was for their researchers located across the country to easily share their work ... initially it was just used to share papers, before Ray Tomlinson invented email. Beyond that, JCR Licklider who laid the conceptual foundations was looking toward something along the lines of today's Internet + AI:
https://en.wikipedia.org/wiki/Man%E2%80%93Computer_Symbiosis
P.P.S. Steve Crocker's MIT PhD thesis was on man-machine symbiosis. I know this because he mentioned it to me when I met him in the UCLA Computer Club which he came to because he wanted to teach an informal class on LISP and Theorem Proving, and the club organized such classes. We got to talking about his thesis, he posed some challenges to me that I got lucky in solving, and he immediately offered me a job (he was the head of the ARPANET project at UCLA, under Leonard Kleinrock) that shaped the rest of my life--I'm greatly indebted to him.
Y.A.P.S. Steve Crocker received the Jonathan B. Postel Award (created by Vint Cerf) last year.