You could hack critical infrastructure before AI. Any and all of the bulk internet scanners have had lists of exposed critical infrastructure for quite a while now. At first it was shocking that nothing ever got done about it, then it became routine.
All that AI has done is to lower the bar of entry for criminal activity. Which is a concern, but it's not the primary concern. The primary concern remains that so much critical infrastructure is poorly secured.
The bigger problem here is that you can hack everything, all at once, for very cheap.
Don't get me wrong I have general disgust towards these companies that are trying to get regulatory capture on AI when they can't even secure their own systems. I believe if people know that a random AI agent can hack their systems they will put in a lot more effort into making sure it doesn't happen. This is a personal example, but I didn't really care about securing few systems as I knew no human would be ever interested in finding a vulnerability in proprietary software, however, AI has no concept of that and would hack a random rpi server running a completely undocumented unknown API just because it can't distinguish value and it costs nothing.
There’s obviously a strong interaction between the hackability of the target and the economic value of hacking the target.
Perhaps the latest models change that relationship in a meaningful way.