Usenet didn't fail at all, it just went out of fashion after Google killed the usenet archive. Honestly, I think if we applied everything we've learned about http over the past thirty years and applied it to an updated nntp protocol then it would be quite formidable.
The biggest issue that never was never resolved was on one hand you have the people who don't want people controlling what they read and say - and on the other hand you have the jerks that want to abuse that. If you've ever logged into a darknet forum and someone has uploaded hundreds of autopsy photos anywhere they could upload photos except the "autopsy photos" area, then that is exactly what used to happen on Usenet. It's probably the same guy doing it. Though personally I think having to do the occasional bulk delete is worth preserving freedom of expression.
The biggest issue that never was never resolved was on one hand you have the people who don't want people controlling what they read and say - and on the other hand you have the jerks that want to abuse that. If you've ever logged into a darknet forum and someone has uploaded hundreds of autopsy photos anywhere they could upload photos except the "autopsy photos" area, then that is exactly what used to happen on Usenet. It's probably the same guy doing it. Though personally I think having to do the occasional bulk delete is worth preserving freedom of expression.