Elon Musk unveiled Tesla Inc.’s highly anticipated self-driving taxi at a flashy event that was light on specifics, leaving investors questioning how the carmaker expects to achieve its ambitious goals.

Tesla CEO Elon Musk unveiled on Thursday his vision of a “a fun, exciting future,” an “age of abundance” full of his company’s self-driving cars without steering wheels, parking lots turned into parks and robots that will walk among the population – that he once again promised would be available within a few years.