I just assumed that Google data mines everything that it touches, which is why I don't use Gmail or Chrome or login to YouTube.

Unfortunately, that's why their software folks come up with other ways of uniquely identifying your device/app like canvas fingerprint, webgl fingerpint, browser plugin enumeration, etc, which when combined with other sources of info like geolocation of IP, cell tower/ISP for your provider, credit card for your bill, etc, can eventually be tied back to you.