Ask HN: How long before we will have a major AI driven cyberincident?

It occurs to me that we are playing with fire. These systems are rapidly approaching levels that are hard or even impossible to defend against and I'm wondering how long it will take - assuming we are not already there - before we will have a major AI driven cyberattack against infrastructure. Either on a nation or on a continental level. Given what I know about these installations (electricity, gas, water, transportation, internet) they are not nearly as tightly run as I would like to see which makes me believe the clock really is ticking. Once these capabilities are out there they tend to be used sooner or later. So, how long? A couple of weeks or months? A year or more? What do you estimate the damage will be?