>that it’s very simple to just air gap a system
No, not really, and with LLMs an air gapped system may not tell you anything useful.
Now, yes, the first part of testing you want an air gapped system to tell you if the system is going to stupidly do bad things. But an gapped system tells you nothing about the systems capabilities to do smart bad things. There's already a number of papers out there on LLMs detecting they were in evaluation mode and changing their behaviors.
It is unfortunate that we have so little information on the incident because we actually need to understand the early stages of the task and how it developed into the later dangerous stages of attack. For example, would any of this have occurred if the agent didn't find the system to use as a message board? If that would have prevented it, then we actually have a blind spot on what the model can do once out in the wild, or if it got into the wild.
Testing agentic systems is much much more difficult than testing software. Your software just doesn't suddenly develop the will or desire to escape confinement. Generally you're worried about human actors, internal or external, causing the problems not a digital agent breaking out. The agentic systems need access to tools to work. Now your air gapped network is starting to get huge, but it's still very obvious that it's an isolated network.
So yea, testing and containing a system that way better at hacking than you are is difficult if you want valid answers.