Oh yeah, we need a purely unfiltered web to prevent echo chambers forming! Let's see what that turns out like—oh that's right, 4chan. (Do we really need more 4chans?)
It looks like even with an unfiltered world, echo chambers still evolve. It's the nature of communities.
4chan isn't unfiltered. People left it in droves for sites like 8chan because they found the moderation of 4chan too restrictive. 8chan also isn't unfiltered. Neither is Voat, which is where everyone who found Reddit too stifling wound up. No site on the open web is truly unfiltered, because that would allow for illegal content, and the men with guns in vans are a real thing. Too many people mistake the freedom to be intolerant, rude or uncivil with free speech.
>Do we really need more 4chans?
Yes, if by "4chans" you mean anonymous platforms. That doesn't necessarily mean we need more of the toxicity at the bottom of the cesspool that imageboard culture is known for, but I do think we need more sites which push back against the hostile patterns of social media, which include "real name" policies and moderation or filtering that tries to shape communities from the top down.
The truth here is that one person's echo chamber is another person's culture, and that "unfiltered" is just another kind of echo chamber.
I think this academic search for an example of purely unfiltered community is getting in the way of the practical point that communities, however filtered they are, are clearly more or less filtered relative to one another, and that yields observable effects.
4chan is clearly less filtered than reddit, and we can see how differences in the degree of filtering creates a race to the bottom.
4chan is too restrictive for some people who want to race to an even deeper bottom, and on and on.
>That doesn't necessarily mean we need more of the toxicity at the bottom of the cesspool that imageboard culture is known for
But the whole point is that the less filtered the community, the more a toxic lowest common denominator develops, which is not preferable to the things decried as "echo chambers" in more filtered communities.
It looks like even with an unfiltered world, echo chambers still evolve. It's the nature of communities.