I've been slowly writing a version of Reddit with an added level of moderation via direct democracy but made efficient by using proxy votes and statistical sampling. People with time and interest provide most is the content but moderation incentivizes behavior beneficial to the majority.
It's a fools errand as it's a double-sided market but I feel the need.
Moderation itself is an attempt at a solution. And it is a solution on a small enough scale. But when you're literally dealing with moderating the entire world 24/7, there just aren't the resources to deal with that.
You're attempting to automate that or kick that can back to the users. But just like here, just like reddit, just like StackOverflow, just like every single site that relies on community moderation that gets big, time beats all.
It'll be fine for a while and you'll think you've solved the issue, but then you'll tip and become larger than you can socially manage. And those with the most time will skew your samples and votes.
The fundamental issue of any fully open community is scale. From what I've seen, no online community really resists the swarm that comes when it goes viral. Whatever community that was there before, for all it's values and culture, gets replaced by the masses by sheer virtue of numbers.
Gatekeeping (or moderation) works, but like we've both already said, it only works for smaller scales.
Do I have time to make 4 or 5 burner accounts to enforce my votes? No. I have things to do.
Do I have time to post ad nauseum about any given topic to make my point? No. I have things to do.
And I'm sure you have things to do as well, so do a lot of people. But those that don't, have the thing we lack: time. And there's often reasons they have all that time. Often good reasons. And it's not because they're pleasant people.