Ask HN: Why doesn't browsers enforce privacy regulations?

For years cookie warnings have been the toll we have to pay to use websites in the EU. Ugly, annoying, mobile unfriendly.

Now with GDPR we face further consent notifications, and a new ePrivacy directive is on the horizon.

This makes me wonder - why haven't these consent notifications been standardized in browsers - it seems like just the kind of thing that would benefit consumers as well as businesses, and who better to enforce cookie rules than browsers?