ARPANet survivability wasn't the initial goal.
"Pretty sure that the US DoD funded ARPAnet to create a network that would be able to withstand a Soviet attack, by routing around destroyed nodes."
Not really. According to Charles Herzfeld, ARPA Director (1965–1967): "The ARPANET was not started to create a Command and Control System that would survive a nuclear attack, as many now claim. To build such a system was, clearly, a major military need, but it was not ARPA's mission to do this; in fact, we would have been severely criticized had we tried. Rather, the ARPANET came out of our frustration that there were only a limited number of large, powerful research computers in the country, and that many research investigators, who should have access to them, were geographically separated from them."
Of course, nuclear survivability probably didn't hurt when people were discussing funding, but that wasn't the main goal. The underlying systems were unreliable enough that they needed the robustness anyway.
Biting the hand that feeds IT
