And hyperloop could, theoretically, move people and goods at several times the speed of sound for cheap, once the vacuum is established. Much faster than any other current method.
As to Musk being overhyped, he sold a game he programmed at age 12, was founder or co-founder of zip2, PayPal, spacex, tesla, and is credited with the concept of SolarCity. The only other person I can think of with that kind of diversity is Richard Branson. Maybe Paul Allen, but everything he's touched since Microsoft has failed. He certainly isn't always right, but he seems to have a knack for founding companies that work in areas that are just ahead of the curve.