I showed Zapier's CEO three versions of the same PM work and had him grade each one live against Zapier's AI fluency rubric. A PRD written with ChatGPT: Capable. He named what was missing. No prototype, which he now expects because AI makes one cheap. And no evidence. Where did customers ask for this? Gong calls, Zendesk tickets, Reddit threads, posts on X. His line: "If there are things I know that you don't know, that's probably not a great signal." A working prototype plus a PRD that…