Such platforms already exist. Also, more government is not a solution. Government tends to create more problems than it solves. It also creates opportunity for corruption. I truly believe Facebook would be an even slimier platform if it were run by the government. The network effect of Facebook and Twitter is real. Even Google couldn't crack that nut coming late to the party with it's Google+ social network. It's been running since 2011 and they recently decided to pull the plug this April. This is probably the biggest barrier. Users with Stolkholm syndrome, or who are blissfully ignorant about how they are being abused and manipulated. There are decent open-source decentralized alternatives that exist, such and Mastodon, Minds, and Secure Scuttlebutt. There are other up-and-comers. But they aren't widely used. Mastodon and to a lesser extent SSB have left-leaning users making up the majority, but anyone is free to set up their own instance. Here's an article whining about the lead developer (written by a lgbt reporter).