Governments are now obsolete, the world just hasn't figured it out yet.
They are not yet obsolete.
I have hopes, and I am working hard on making at least some aspects of them obsolete, but for now anyway, it would not be prudent to attempt to form a working society without any.
Bitcoin's blockchain is an example of "self enforcing law" -- in particular people don't counterfeit bitcoins because they can't. People don't misrepresent amounts because they can't. It's all set up by protocol and enforced because enough ordinary people who don't want to be the victims of those crimes continue to honor the protocols that protect them. I applaud the concept.
If we can extend it to cover most kinds of commodities trading, in a way that most of those crimes cannot be committed either, that will be a huge step toward obsoleting more functions of government. It would be a huge win for everybody, a relief of that part of the tax burden combined with a relief from that kind of crime.
But I have to believe that we will always need someone whom we can rely on to respond if some idiot stands up in a theatre and starts shooting people, and I can't come up with a cryptographic protocol that would prevent that.
Not saying that government won't be completely obsolete within a century or so, but understand that to make government completely obsolete will take an AI capable of faster and more accurate thought than humans, fully capable of using force, and not under human control. Right now I consider that more than a little bit scary.