Another thing that people persistently misunderstand is the scale relationship between GCP and the rest of Google.

Even if all you say is true and it is truly impossible for the government to replicate any of what Google does, the point is moot. If the government is going to appropriate Google's index, might as well appropriate the datacenters too. Really, whats Google going to do with them once search is gone? According to you, it is the only thing they have have running there.

Might as well appropriate the engineers, too, and chain them to their desks and force them to keep everything working.

Truly an absurd comment. The US government is the largest employer in the country, with something in the order of 10 million employees. Are they all slaves chained to their desks?

It also does a lot of storage intensive, non search related stuff, like Google Cloud Storage.

Every Google data center does...everything.