One of the most common mistakes people make when discussing the data collected by someone like Google is only considering the data in isolation. In reality, data is often combined with other databases.

[1] The minimum number of data points might can be very small: handful of timestamped locations at your home and job is probably unique, matching browser fingerprints if you used the same browser for logged-in and not-logged-in activity, or - as this is Google and their OS - maybe even simply a single even: hearing a MAC address known to be om your home wifi over the radio.