In 2013, Elon Musk published a white paper that teased the idea of zipping from Los Angeles to San Francisco in just 35 minutes through a vacuum-sealed tube -- a system he called hyperloop. The idea “originated out of his hatred for California’s proposed high-speed rail system,” according to his biographer Ashlee Vance. Ten years later, the most high-profile startup that tried to follow in Musk’s footsteps -- Hyperloop One -- is closing its doors.