> No, we're talking about accounts who already had it (as part of broader setting) disabled for them, in a context where the data in question can (contractually) only be used to provide the service anyhow.

That doesn’t contradict that it was switched off intentionally.

> Pray tell me how you can do client side search history recommendation for the first query I make after logging in.

Logging in to what? Are you saying you want your search history synced between your browsers? If so, that’s a solved problem that doesn’t require Google to track you.