But that's only a small part of a huge legal frame, and as I said I don't know much about these problematics.
You can still turn cookies off in your user agent though.
That was the missed opportunity. Had the EU stepped in and said "I'm sorry, the user expressed explicit intent to not be tracked and you're planning to ignore that? How about that's a fine?" it would have survived.
But they weren't prepped to take action yet.
The only reason why the advertisers were so unhappy about it is because what they do is neither good nor sensible by most people's standards.
If I (a complete stranger to you) walk up to you and kiss you on the lips, it doesn't make a difference whether you're wearing a t-shirt informing everyone you don't want strangers to kiss you on the lips or not - I don't have any basis on which I can presume to have obtained your consent so I'd still be violating your rights.
This is very much a "tech bros don't understand consent" case: if you do something without consent, you better have a damn good reason other than "but it's good for meeee" (or "good for my bottom line"). "My business model depends on it" also isn't a good justification - there are plenty of business models that depend on things that are unquestionably illegal, we just refer to them as "criminal enterprises" rather than "disruptive startups".
Actually it's worse, DNT headers are like posting a wall of text on facebook saying you do not consent to them using your images or posts for some purpose.
Track doesn't have a consistent definition across contexts, to regulate this you would have to fix it to something - what are your suggestions? DNT and the "deny optional" that foamed its way out of the GDPR aren't quite the same thing, and even if they are, it will take many court cases and years of time to figure that out.
If you have a better write on regulation lets hear it.
Or it will take one clear message from the regulators saying they're equivalent.
What most people miss about the GDPR is that most of it (as well as the ePrivacy Directive covering more technical aspects like cookies) really only exists because of the one big thing at its core most people are either not aware of or intentionally omitting:
The GDPR establishes a user's right to ownership and control of their personally identifiable information as an inalienable and irrevocable fundamental human right. This is what makes all the rest of it necessary: it's not about "cookie banners", it's about requiring others to obtain consent for what they want to do with that information; it's not about writing "privacy policies", it's about explaining what you do with that information and how you guarantee their rights are respected by you and disclosing who you're passing it on to and how you're ensuring they too respect those rights.
The alternative to consent dialogs (whether as "pop-ups" or via confirmations when prompting for relevant information) would be requiring every website to have a written contract with each user. Consent is only valid if it is demonstrably informed (and non-coerced but that's a different story) and it must be specific and revocable. You can't have users blanket opt-in to everything you'd like - they wouldn't even know what consent they'd need to withdraw later if they reconsider.
By the way, courts recently seem to have started ruling that the way many AIs work the companies training them are in violation of copyright laws by using intellectual property as training data without permission and in order for contracts to be legally binding, anything given by one party has to be given consideration by the other (i.e. anything of value given by one party has to be balanced out with something of value given by the other party) - so I wouldn't be too quick to ridicule the idea that using Facebook means Facebook can do with your data whatever its terms of service say they can do, even if posting on Facebook can probably not be considered an effective way of informing Meta about your disagreement.
The only thing required to make a signal like that legally binding is the power of law. It just wasn't there for DNT.