Nearly four hours into Tesla’s marathon Investor Day, someone in the audience tried again to bring Elon Musk, the Tesla (and Twitter and SpaceX) CEO back to the present day. From a stage at the Gigafactory in Austin, Texas, Musk had announced an ambitious “Master Plan 3” to save the world. For $10 trillion in manufacturing investment, Musk said, the world could move wholesale to a renewable electricity grid, powering electric cars, planes, and ships.