The results from Gregory Kestin's Harvard physics experiment arrived like a thunderclap. Students using an AI tutor in their dormitory rooms learned more than twice as much as their peers sitting in active learning classrooms with experienced instructors. They did it in less time. They reported feeling more engaged. Published in Scientific Reports in June 2025, the study seemed to confirm what education technology evangelists had been promising for years: artificial intelligence could finally crack the code of personalised learning at scale. But the number that truly matters lies elsewhere. In September 2024, Khan Academy's AI-powered Khanmigo reached 700,000 students, up from just 40,000 the previous year. By the end of 2025, projections suggested more than one million students would be learning with an artificial tutor that never tires, never loses patience, and remembers every mistake a child has ever made.…