A promise that skips the proof stage is a story, not a product.
Theranos pitched a full lab in a finger prick, and investors, partners and the press bought the pitch before anyone outside had checked the machine. The book shows the company's own Edison device could not do what was claimed, so many tests were quietly run on modified commercial analysers made by other companies. The question that would have caught it early was simple: who outside the company has seen this work?