To see why, let's focus on what the problem actually is: we're social animals who crave authentic connection with others, not just to hear but to be heard. We can't just be passive consumers of news but wish to comment on it and be heard and replied to and have meaningful discussion. The problem is that a voting bloc systematically muffles some peoples' speech, ostracising them from the community due to their disagreement -- but then the community becomes an echochamber and fails to satisfy our needs for diversity.
One solution to this has been randomization -- think Omegle etc. -- which works but encourages a different sort of inauthenticity due to anonymity. Another has been the Reddit/LiveJournal model: make it easy to spawn new communities when old ones die out. It's a lot less clear why, say, LiveJournal has mostly died, but probably it was a little too egotistical and people therefore as they grew up got bored with just sharing their own viewpoints without some sort of cohesive blogging narrative, and it just died.
Somewhere there's some room for a solution which batches together communities of 50 people more-or-less randomly with some form of self-selection, and encourages them to talk about some sort of topic-of-the-day that would be relevant to all of their interests. In the meantime our solution is to join a social network and have fun until our community gets too large and we cannot get the attention we crave, at which point we'll swap to another and repeat the process again.