I agree with your premise, but not your conclusion. The problem is not the scope or scale of things, but treating them in an absurdly stupid fashion. Why are power systems internet connected? It certainly enables some greater degree of power and flexibility, but it exposes them to potentially catastrophic outcomes in case of malfeasance. So what happened at some point is somebody convinced somebody else that the security was super duper ultra good, and that's simply not true.

And I'd go one step further to say that it probably can not be true. This has always been true and probably will always be true. All LLMs are doing is demonstrating that. And the LLMs of tomorrow will demonstrate that the most LLM hardened system of today is still just a vulnerable mess. So the conclusion is simple - things should not be connected to the internet unless the worst case scenario from hacking/exploiting is relatively low. If somebody wants to connect their coffee maker to the internet, for one can only imagine whatever reason, then the worst case scenario is a broken coffee pot - who cares, go for it. But connecting e.g. power, water, or other core infrastructure to the internet? No, never.

Just because something hasn't been proven to be a problem today does not mean it won't be a problem tomorrow. We shouldn't learned that yesterday, hopefully we can learn it today.