It isn't just tracking. It is an entire system of profiling. Your personal history.
Consider… Google is putting an end to Hangouts. It is building a new tool for companies to use for business. Let's say it has a sort of 'employee background' service at some point in the future.
Not all tracking needs to be for 'hard' control or kill methods. Google might be able to tell you're a damned good engineer, but knows you are conservative and against it. So, they keep you away from jobs and positions where you can cause damage to Google using a background index or something similar.