You're absolutely right. You could probably run Uber with a tenth of that headcount.

The thing is, at a lot of companies - and I'm guessing Uber is the same - there's no incentive to have a small team. In fact, managers are incentivized to have a bigger team. Having more reports, and more levels of management, under you is a status symbol. Plus, people use it to justify taking on bigger roles and more responsibility - "better to give the promotion to the person who already has experience managing a 300 person team and already has experience managing managers who manage managers than the person who's been making do with 10 direct reports."

So a lot more people end up getting hired than perhaps are really strictly necessary. It's a dynamic that probably most high-growth companies fall into at some point. You have to really consciously make an effort to stay lean if you want to.

Of course, what's wrong with having a little fat in the workforce as long as you have plenty of cash in the bank and can still operate effectively? Even if the hiring is driven in part by execs jockeying for position it's still spreading some of Uber's cash out to a broader swath of people. From a societal standpoint it's arguably better for Uber to employ 12,000 than 1,200 people.