Except all of these things have the same critical flaw; they all depend on advertisements to pay the bills. To get advertisers, they need engaged audiences. To get engaged audiences, they need various social mechanics to drive engagement to an artificially high rate than their service would otherwise have. They also are then incentivized to police content in ways that make the medium more appealing to advertisers. Then eventually people get sick of it, and a new upstart shows up offering a better experience with less advertising. And people move on, until the same factors cause the same cancers to grow in the new one, which eventually cause it's own demise.

Ironically, by banning advertisement, you would eliminate one of the biggest drivers of change in social networks that cause them to die. Not all of them, of course, but one of the biggest by far. In a strange twist, you might well save the social network from succumbing to the cancer it's leadership always inflicts upon it.

The qualities that make a social network useful for the purpose of allowing social networking are almost completely at odds with the qualities that make it attractive to advertisers, almost to a comical degree:

* Privacy controls and default-enabled secure settings hide information from advertisers

* Securing people's social circles from advertisers reduces their ability to target

* Protecting people's photos from being co-opted for use in apps or scanned for auto-tagging reduces reach

* Policing outrageous, clickbait, or controversial content reduces the main clients social networks have for paid promotion

Basically, the ideal social network would either charge a base subscription fee and provide an ad-free experience, or would be free, and be entirely subsidized by the Government. I cannot envision a private company willing to provide a user-centered experience that would be a net good for the userbase, because everything the users want and need conflicts with what the network would want to sell to advertisers.

A government run social network would probably come with so many strings attached that it would never work. It wouldn't appeal to people because you wouldn't be allowed to say or do most things. Even if draconian rules don't exist at the start, they will quickly appear.

Care to enumerate some of these strings? Or perhaps some of these things you wouldn't be allowed to say?

Quite the contrary on the second point, with regard to a Government-run website, you'd have a far stronger claim to the rights of free expression people regularly (erroneously) attempt to claim on privately owned social networks.

Or does your entire point begin and end with "government bad?"