Comment by kube-system

>The browser ultimately sends only what the webpage requests.

You've got 6 layers under your browser before that data is sent -- some of those are useful for fingerprinting. Also, browser behavior and feature sets are not and likely will never be 100% uniform.

> GDPR to make it illegal for browsers to track this information

Unfortunately the internet is global and people outside of the reach of those jurisdictions can just exist outside of the reach of those laws. Consider the existing landscape of malicious internet traffic and scams which are already illegal in almost every country -- they are still a widespread problem.