This is 100% about reinforcing Google's ad monopoly (along with the AMP initiative). Google owns DoubleClick which is the biggest adserver on the planet and the #1 source of all the bad intrusive ads in the first place. This could've been easily solved years ago.
Most people think Google's push for HTTPS, both in Chrome and SEO rankings, is somehow related to privacy.
It's not. It's about net neutrality and it's about third parties being able to switch out Google's ads for their own, on-the-fly, using a middleman.
I interviewed with a stealth-level startup a few years back. They were developing a product, similar to a WiFi router, that would be installed on premise and sit there, filtering out Google/Facebook/etc. ads and replacing them with ads that the owner of the box wanted. You can imagine this box being installed in Starbucks, airports, libraries, and everywhere else. Cutting into a massive chunk of Google's ad revenue.
The Time Warners, AT&Ts, and Verizons of the world would also be doing this, for HTTP traffic.
We are getting the benefits of privacy. But it's not because Google has good intentions.