It's a taxi company. They have a web site and a mobile application, but so does several retailers as well as pretty much every bank out there. And no one is accusing them of being tech companies, or expect their growth to mirror that of Google or Facebook.

If you just look at the business of Uber, it's clear their current business does not inspire confidence that they will ever be profitable, much less deserving of Google-level valuations.

Sure, they may be able to become successful, but that would be on the back of a different business model. But then you'd have to justify why Uber would be able to execute on this as-of-yet-unknown business model better than any competitor.