GDN is not the only piece of business that'll be impacted by strong user privacy. Search and YT will also be impacted, given there's ability to buy ads based on users being in-market for a product/service etc [1]

You can also be targeted with ads based on emails you receive in Gmail - it was possible to target down to keywords in emails, but that was discontinued. Now, the emails you receive, domains your getting them from etc. influence signals, that puts you into an 'audience' that can be used for targeting across the Google network.

Without the ability to do targeting, or personalization, as Google calls it, their business will fall apart. Everything they do is geared to collecting more information about users to improve "personalization" - from Google Assistant, to Google Home [2]. It's so advanced that your experience (results) on their platfrom, especially within Search -- will be unique to you.

Google will fight alongside AT&T, Comcast, etc to protect their business model, in-fact Google is trying to reach their ranks with the 5G war [3]

[1] https://searchengineland.com/google-adwords-in-market-audien...

[2] https://twitter.com/benthompson/status/864293485439893505

[3] https://www.bloomberg.com/news/articles/2018-03-29/google-le... - (search for: Spectrum Access System )