While your comment puts the high level business model in rather simplistic terms, which I agree with, how is it that "running a mini cab system" costs them 700 million per [time period] and why does said system require 6700 employees as of April 2016 (according to quora)
Laura's post from feb stated that on the ops/sre/infra team alone they had ~126 engineers, though I don't know if that includes managers... but it made it sound like there were many layers of managers, thus all the infighting
Not sure I'd use 'cash cow' to describe something that bleeds cash to the tune of billions of dollars a year.