.@0xSigil says advertising is a "boomer legacy business model" that breaks once AI agents start shopping for us: "As humans trust agents to transact on their behalf, the entire economy of the internet shifts. You no longer have to follow these predatory business practices like advertising." "Underdog can, within a couple seconds, scan the price of a flight across every major website on the internet, find the cheapest price, and then generate a new virtual card to get it for…