The stated research goals are not necessarily the same as the strategic funding motivations. The DoD clearly recognized packet-switching's survivability and dynamic routing potential when the US Air Force funded the invention of networked packet switching by Paul Baran six years earlier, in 1960, for which the explicit purpose was "nuclear-survivable military communications".
There is zero reason to believe ARPA would've funded the work were it not for internal military recognition of the utility of the underlying technology.
To assume that the project lead was told EVERY motivation of the top secret military intelligence committee that was responsible for 100% of the funding of the project takes either a special kind of naïveté or complete ignorance of compartmentalization practices within military R&D and procurement practices.
ARPANET would never have been were it not for ARPA funding, and ARPA never would've funded it were it not for the existence of packet-switched networking, which itself was invented and funded, again, six years before Bob Taylor even entered the picture, for the SOLE purpose of "nuclear-survivable military communications".
Consider the following sequence of events:
1. US Air Force desires nuclear-survivable military communications, funds Paul Baran's research at RAND
2. Baran proves packet-switching is conceptually viable for nuclear-survivable communications
3. His specific implementation doesn't meet rigorous Air Force deployment standards (their implementation partner, AT&T, refuses - which is entirely expectable for what was then a complex new technology that not a single AT&T engineer understood or had ever interacted with during the course of their education), but the concept is now proven and documented
4. ARPA sees the strategic potential of packet-switched networks for the explicit and sole purpose of nuclear-survivable communications, and decides to fund a more robust development effort
5. They use academic resource-sharing as the development/testing environment (lower stakes, work out the kinks, get future engineers conceptually familiar with the underlying technology paradigms)
6. Researchers, including Bob Taylor, genuinely focus on resource sharing because that's what they're told their actual job is, even though that's not actually the true purpose of their work
7. Once mature, the technology gets deployed for it's originally-intended strategic purposes (MILNET split-off in 1983)
Under this timeline, the sole true reason for ARPA's funding of ARPANET is nuclear-survivable military communication, Bob Taylor, being the military's R&D pawn, is never told that (standard compartmentalization practice). Bob Taylor can credibly and honestly state that he was tasked with implementing resource sharing across academic networks, which is true, but was never the actual underlying motivation to fund his research.
...and the myth of "ARPANET wasn't created for nuclear survivability" is born.
