People still use email for all kinds of business, of course. But their day-to-day personal activities, the kind that marketers care about ("I've taken up kayaking!", "I'm pregnant!") don't usually show up in emails any more, they get posted on social media.
Speak for yourself, I don't like to imagine that at all.
As it is, they're presumably still reading our gdocs, address books, calendars, hangouts, search histories and broswing histories, and geolocations/third party app usage for all the android users. Email data is white noise compared to this.
I'd wonder how IT could be so stupid to put up with this if Microsoft hadn't also made pervasive surveillance mandatory.
So you haven't worked in an industry where you had that data and tried it then? In my experience you are completely, utterly wrong.