DNT is flawed. As an user, I have no way to verify that DNT is honored. As such, I assume nobody respects DNT and proceed accordingly by taking my own tracking countermeasures.

You can also assume DNT is pretty much ignored. For instance, if I set DNT and I visit a website adhering with those EU cookie regulations, while I'm still being shown that cookies are being used to track me and that by using the website I agree (never mind that 3rd party cookies are already being sent)? I already stated that I do not want to be tracked.

Oh, but maybe you would assume setting the DNT preference in the browser does something meaningful, such as disabling 3rd party cookies, disabling beacons, ServiceWorkers and cache lifetime?

Nope. There is no point in honoring DNT: you are either tracking or not tracking your users depending on which resources you're including on your website. If you don't want to track your users, do not include 3rd party resources. If you do include 3rd party resources, then it's it's up to the 3rd-party to honor DNT.