Do you actually believe it will delete anything? You're wrong. NSA would still get the data, and so would Google for marketing purposes. It's just to calm privacy-aware, but not techsavvy users.
If you don't want the NSA to gather information on you, the GDPR will not address that.
If it is illegal for google to collect the data, then the NSA can't force them to or subpoena the non-existent files.
The NSA will collect it on the wire anyway. They have drilled in and tapped underground fibre optic cables on private networks behind HTTPS load balancers before, and simply captured what they want.
How do I do that if I don't have an account? Also, if I do have an account, will that delete all of the crap doubleclick and friends shared with each other while I was logged out?
What does this definition of "opt-out" mean?
The code in their tracker stub (always inlined as a <script> tag) is rendered inoperable.
Google stores many of those settings as cookies, which means your opt-out only applies to one browser on one device for a limited time.
I don't login and regularly clear my cookies (pretty much whenever the first targeted ad gets past my adblocker).
I wonder if there is a browser extension that will auto-opt-out of all 1,000,000 (or whatever) trackers on the internet each time you clear cookies.
You can use ghostery.
I wouldn't trust Google in anything, especially opt-outs.