The problem with DNT was that there was no established legal basis governing its meaning and some browsers just sent it by default so corporations started arguing it's meaningless because there's no way to tell if it indicates a genuine request or is merely an artefact of the user's browser choice (which may be meaningless as well if they didn't get to choose their browser).

As the English version of that page says, it's been superceded by GPC which has more widespread industry support and is trying to get legal adoption though I'm seeing conflicting statements about whether it has any legal meaning at the moment, especially outside the US - the described effects in the EU seem redundant given what the GDPR and ePrivacy directive establish as the default behavior: https://privacycg.github.io/gpc-spec/explainer