> If you don't update your local software then it will certainly become automatically backdoored by an accumulating series of security vulnerabilities over time.

Y'know though, when you put it that way, it sounds inherent that security vulnerabilities will pop up, which is kinda true, at least for the foreseeable future, but to be pedantic, the security vulnerabilities are already there, it's discovering them that's the problem. If we could make secure computers... (time to formally prove everything from the ground up I guess.)

But, that said, I wasn't overlooking this, I'm just looping "getting pwned" into "active involvement". If you have some sufficiently isolated machines, they're probably fine indefinitely. The practicality of this is limited outside of thought experiments. However it's definitely worth noting that unlike a compromised remote, it is at least technically feasible to work on the problem of making local compromise more evident, whereas a remote compromise is truly impossible to reliably be able to detect from the outside.

> If you have some sufficiently isolated machines, they're probably fine indefinitely.

The eternal dream of unplugging, and living free on Amigas.