I understand the theory of how it is intended to function. The only SHTF market scenario I've seen that had a chance, was a location where if you stole or threatened force; they hung you. The market wgot a percentage for the harsh security. 

When the SHTF happens, markets will not be unicorns and flowers; they will become life or death! Voluntary actions will cease to exist, unless backed by a threat of force. 

When things break down, force will sadly be the only remaining safety! No consensus or agreements that are not backed by obvious threat of force, will get a lot of people killed.  The the wild west was tame by comparison, because people back then had moral absolutes; today that is no longer true...they will steal the gold out of your teeth! So don't bank on human nature, because that nature is spotty at best

If you set up a community using anarchy, you better have armed guards and a defense plan; or you will soon have a boot on your throat. Not good, but sadly predictable. Also avoid markets for as long as you can, to allow the most violent to be filtered out...by counter violence!

When the government fails, violence will replace the Constitutional rule of law. This is unavoidable, as power flows into a vacuum. 

All government is a necessary Evil, to avoid being overrun by a foreign power (provide for the common defense). If the breakdown is deep enough, we may see some of that too. 

If you have enough force, to stop all encroachment; you run the rusk of forcing your neighbors to comply with you cherished model. If you do this, you become the tyrant you want to avoid! 

A Republic is the least invasive form of evil government, but the politicians need to be forced to abide by Constitutional restrictions. We have not enforced that restriction, so the politicians are following the same greed and hunger for power; and trying to set up tyranny. 

They damn near finished us just before WW2, but were forced back to what worked by fascist in Germany and Italy, as well as the fanatics in Japan. Our 'government' is now copying the National Socialists game plan here!

I have never thought that government offers solutions, but there is a need for common defense. The Republic is the least invasive way to get that.