Earlier quoted context omitted.
How would not respecting DNT have been proven? The rub here is that everyone wanted to ignore DNT, because it made them lots and lots of money.
How can you prove that they respect your preferences in those consent theater pop ups? I think those pop ups are the worst thing that ever happened to the web because they eliminated the moral authority that anyone had to say “it is user hostile to use pop ups”. Once the EU made it appear “required” and even “laudable” or “prosocial” there was no basis to say “you shouldn’t put this other popup in that will make user…
I suppose the formalism around popups, and specifically when the EU decided to start levying fines on entities who used dark patterns to avoid the spirit of "accept/reject must be equally easy to click", convinced me that user-visible was a better way to win the fight.
Granted, it's not a technically optimal solution, but it may be a politically optimal one. Vis-a-vis the people vs the advertising industry.
I'm unconvinced that DNT would have ever garnered the same support as something that people, and specifically politicians, can see. Which would have led to ad money quietly carrying the day.
I'm hopefully after we've chiseled "Thou shalt respect user decisions" in stone deeply enough, we can flip back to enabling a user agent to automatically respond to that question for us.