I would argue society would come to near-collapse with just the internet shut down. If we are talking about no power grid, then anarchy and millions dead in just a few days. Or Mr. AI could display fabricated system data to nuclear power plant operators, blackmail some idiot with their nude photos to give up rocket launch codes, or crash the financial markets with a flood of fake news. I am no way a doomer, but these are logically explainable scenarios utilizing existing tools, the missing link is an AGI who is capable and intends to orchestrate these.