Take a look at Uber's career's page. Even broken down to USA Engineering on the Engineering team hires, there are dozens and dozens of open positions. It's safe to say Uber thinks it's a > 20 person job.
I agree with you and parent that it is (and should) be a > 20 person job for its scale, but the career page is probably not the best example.
Many of those positions are perpetually open or rotated periodically (see: "You're leaking trade secrets" by Michael Schrenk) while the actual position was given to someone internal or someone connected to someone else internal to the firm.
Most of these pages are used for resume harvesting so that [if the firm has resources] an HR or technical recruiter can periodically evaluate the rest of the field. The firms holding out for the "rock star" often are more aggressive in recruiting them (whether at Job fairs or through LinkedIn headhunting).
https://www.uber.com/careers/list/?city=all&country=united-s...