Elon Musk’s latest prediction that “money won’t matter” within a decade drew swift online mockery—but a closer look at how fellow tech billionaire Vinod Khosla responded reveals a more sobering warning buried beneath his apparent agreement.

In a wide-ranging interview with The Economist, Musk told editor-in-chief Zanny Minton Beddoes that AI and robotics will produce such an abundance of goods and services by 2036 that money will become irrelevant. His logic: “What do you want money for? You want money for goods and services”—and once robots and AI generate more of both than any human could consume, currency loses its purpose. Musk went further, predicting deflation, not inflation, would become the era’s defining economic challenge.

Musk made similar remarks on the People by WTF podcast months earlier, saying “money disappears as a concept” once AI and robotics can satisfy all human needs without wages acting as “a database for labor allocation.”

What changed this time was the venue and the pile-on. Gizmodo characterized Musk as melting down over “perfectly normal questions” about his worldview, calling his answers frequently incoherent. On Reddit, one widely upvoted thread set off a round of debate, ranging from Musk’s track record of predictions to the future of capitalism.