Have you considered the possibility that someone on the inside works for an intelligence agency (domestic or foreign) and is secretly exfiltrating the data for the purpose of obtaining blackmail material?
In the PRISM disclosure of 2013, the slide deck stated that the NSA had direct access to Google's systems. The deck claimed "collection directly from the servers". That, by its very design, goes around all the safeguards people are discussing here.
It's definitely been considered because it has definitely happened before (explore the history of Google cutting ties with China for about a decade).
... in response, Google took measures to prevent that category of insider-knowledge attack. With audited builds, zero-trust internal model (xref BeyondCorp), and infrastructure cross-checked by multiple human beings to guard against hardware-level attacks, such an insider attack is infinitesimally probable now.
