I think another reason Do Not Track failed is that advertisers (e.g. Google) didn't like it. Microsoft setting Do Not Track on by default in Internet Explorer was likely the death knell.
The industry-led-initiatives are all basically bad, for the obvious reasons. So many of them amount to telling ad networks whether or not the massive amount of data they have collected about you should be part of the consideration for what ads to show (for now) — many offer no possible way to opt out of recording and storing such data in the first place.
This is a situation where legislation is probably the only answer.
A standard written for advertisers by advertisers. This is the problem. There are technical solutions, but the biggest advertiser (Google) makes the browser. This is the same as "the revolution will not be televised." The adversary controls the medium.