I used Usenet before the Eternal September.
The reason it worked back then, is because to a certain extent, it was a relatively homogeneous group of users, meaning, people of comparable education, interests, etc.
I'm not really interested in sharing a newsfeed with a kitchen cabinets spammer or a Russian troll or some MAGA trumpet endlessly gazing upon Hillary's emails, etc.
Also, the legal landscape is different today, we're a long way from a pre-DCMA world. Usenet servers act as common carriers but they are not legally common carriers (in my opinion) which means if I am right, the experiment will end as soon as someone decides to litigate against a server operator for passing on material that someone felt offended by. Not even copyright violations, just something they were offended by. For example, it is illegal to insult Ergodan (really) and while that law isn't enforceable here, it was elsewhere until recently in places like Germany which still had laws on the books saying it wasn't legal to insult foreign heads of state, etc. So it's just a big litigious mess now. You may have noticed the other year how the right-wing wanted to sue/shut-down the tech companies for being too woke and suppressing their free speech rights, etc.
Usenet was a lovely time and I miss it, but that ship sailed long ago and isn't coming back.