It might very well be overprices (I sold because I think it is) but they got $7B in revenue in 2016 which is hardly no earnings. They make money on every car they sell so it would be pretty straightforward for them to decide to become profitable at the expense of growth and R&D. Now, their stock price assumes they're going to conquer the world rather than settle down to become a profitable small car manufacturer and solar/battery provider so lots of investors would lose their shirts if that happened. But it's an option for the company which makes them very different from the pets.coms of the world.
Revenue is nice, but earnings are all that matters when you have debts to pay. Just look over to the recently IPOed Snap, Inc. for a company with less revenue and more eyeballs!
