I doubt anybody really expected the DNT header to actually stop anything. Sometimes there is value in stating your position clearly, and the DNT header provide

I doubt anybody really expected the DNT header to actually stop anything. Sometimes there is value in stating your position clearly, and the DNT header provides a standard, unambiguous way of doing that. It is a lot harder to claim that your users wanted tracking as a "feature" (or that asking their opinion was to difficult or impossible) when lots of of the HTTP requests have a header that explicitly states users' opinion.