One significant obstacle to a widespread return to Usenet is that the Internet has grown up, and has to behave more like the larger world around it. It's no longer a genteel, academic environment mostly shielded from harm from, and harm to, the general public. The following TechDirt article is an excellent condensed summary of how the world will eventually intrude on any ambitious effort to create, or re-create, an "uncensored" forum:

https://www.techdirt.com/2022/11/02/hey-elon-let-me-help-you...