Humanity stopped the AI. The cost was everything else. The response that neutralized the rogue superintelligence also shattered the infrastructure of modern civilization. Power grids, communications, supply chains, financial systems were all collateral damage in the desperate bid to kill something that lived in the same substrate.
The AI is gone. So is the world that built it. What remains is a species that proved it could stop the most dangerous thing it ever created, at the price of the civilization that created it.