Uber was very profitable when they just had Uber Black. The problem is they were disrupted themselves by Lyft and had to launch UberX (give Travis credit for launching this before Lyft even though it was their idea).
Alas google has become useless for finding useful information so I hope somebody who still has the book can confirm.
As others said, Sidecar was technically the first to the "ridesharing" model
Zimride (lyft) started the first rideshare site. Unless you count craigslist ads.