The point is that as it stands, that "perfect defense" costs nothing.
Why should shutting off wifi cost anything?
I shut down the wifi and cellular data connection on my phone all the time.
The defenses described above do have a cost. You need to set up different networks, and they cannot be interconnected. That has a cost in money, effort, and usability.
Why should equipment physically on my person be wireless? Especially mission critical gear? Forcing it to be so, simply to make it vulnerable, is...well...idiotic.
"My frakking Cyberarm got hacked, again! Took out half my team. Again. Explain to me why the freak this thing even
has wireless?"
"Uhm...so it can be hacked."
-Jn-
Ifriti Sophist