Comment by nerdile

It is different when you have a billion customers, all with different setups. At that scale, you notice real defects through product telemetry, support ticket volume, or trusted channels. You receive a high volume of bug reports that are due to user confusion, misconfiguration, or misbehavior of other software on the device - where solving an issue for one customer doesn't result in improvements for the other billion. Triage, filtering, and winnowing are necessary here.