I'd love to see something like this, but in my opinion, there is a reason why none have turned up. It costs a lot of money to run a social network, and people aren't willing to pay to use a social network. That means you're going to have to either rely on advertisements or donations. it's hard to run on donations unless you are large because people mostly don't donate, and many that do only donate a bit. and ads are out so unless you have a reliable plan you are going to be bleeding money and eventually die, or get bought.
corporations benifit from state funded systems, so they should give back to the state. The state funds the streets they drive on, the internet they use computers first created by the government, they use are defended by copyright LAW that the government made to protect companies from copycats, they use money regulated by the government, they use employees that were educated (mostly) by the governemnt, smaller companies benifit from antitrust laws set by the government, corporations benifit from a standardized mail system run by the government, they use a regulated traffic system run by the government, they benifit from a police department run by the government, and so so much more. all these things are run by the government and funded by taxes. it's only fair that they pay their taxes and we need to crack down on tax evasion.