[belorn]

Cookie based targeting is relative easy to remove. It is an early and easy vulnerability that can be quickly addressed before the big ones that takes more engineering and fundamental changes.

Contextual targeting is a bigg problem, and the fix will require a fundamental change. It is almost impossible to use technology to prevent contextual targeting in areas like email service and social media as long as the data is in clear text and available to the server. The current best bet is to use laws like GDPR but it is slow and not something a browser can dictate with a software update.