Derek Thompson revisits his view on whether AI represents a financial bubble, noting that evidence for the argument has both strengthened and weakened at once. He explains that he once believed spending was outpacing revenue but changed his mind after observing explosive revenue growth from new AI agents in late 2025. Investor Paul Kedrosky counters in the piece that AI still resembles historical infrastructure overbuilding like the railroads, where capital expenditure exceeding 50-80% of GDP growth has historically preceded financial crashes despite the underlying technology’s lasting value.
