The man set to become one of the world’s youngest artificial intelligence billionaires started his entrepreneurial journey as a bored preteen living in Los Angeles. When Ali Ansari was 12, living with his family in a single room at his aunt’s house in Woodland Hills, his immigrant mother told him to stop wasting time staring at his phone and try making money with it. He took his father’s loafers and listed them on eBay for $50. “My dad was like, ‘Why the hell did you sell my shoes?’ ” Ansari said. “My mom was like, excited.” While it was a...