> Yeah the DNT header didn't work due in large part to middle men (like routers or anti-virus tools) flipping that bit without asking the user in automatic
A privacy option that's not allowed to be turned on by default based on user data and likely preferences isn't a real privacy option. Advertisers are the kings of trying to guess what users want, did they really think that browsers wouldn't be allowed to do the same with request headers?
This argument comes up a lot, and I'd debate it, but I also think behind the surface-level objections, the heart of the argument basically boils down to, "we didn't realize that people were going to use this thing."
The advertising industry was happy to have an opt-out as long as not too many people used it. Once it started getting turned on by default (because of course a user who's installing antivirus or privacy tools wants DNT to be enabled), Microsoft just became an excuse to abandon the whole thing.
If Microsoft had never turned DNT on by default, but the majority of users had sought out the option and turned it on, then advertisers would have come up with an excuse. Their participation with DNT was a compromise: "you can have a few of these users that probably run adblockers anyway, and in exchange, we want you to get off of our back about everything else."
For these people, respecting DNT always depended on it not being adopted. And that's why trusting them to talk about "responsible ads" or "consumer choice" is a waste of time. They know what they want the consumer choice on privacy to be, and they will only offer that choice as long as the average consumer chooses what they think the 'right' option is. If advertisers discover that the average consumer doesn't want to be tracked, then all of their talk about sitting down and having a dialog is going to go away.