The DNS angle is nice and I get why using a TXT record was interesting for you as a replacement.
I don't think simply having data returned was the issue. It was more about the kinds of data it exposed and doxxed from the user - to anyone with access. That and of course the vulnerability that caused the worm to propagate.
That said - we're seeing RCEs in Node, Python, and other common tools now and they're not going the way of the dodo. So maybe finger's time was simply up - and Facebook, Twitter, etc just took over.
Something ironic about pure text, status info, cgi-bin being replaced by long form video of tigers chasing men and riots. That's what our brains are being fed these days.