== most of the time. The majority of people don't care enough to change the defaults. Most of the time, they don't even think about whether there even is something to change. The overwhelming majority thinks roughly like this: "Ooo, Computer just knows all of this about me? Neat!".

Source: I work in education - even in a highly educated area in a developed EU country, young and old alike think like this.

In the default config the sync data is encrypted end-to-end with the user's Google account password. However, there is also an option to share browser history with Google for telemetric reasons, and it's on by default (regardless of sync encryption settings)

Isn't Chrome Sync opt-out at this point? I seem to recall some small controversy about that a while ago, and setting a passphrase seems like something that it's unlikely most people will do.

A default open browser history synced across devices seems like exactly the sort of thing that would show that DDG has increased its market share.

Sync is opt-in.