You're just begging for a tragedy of the commons, which is a tragedy for a reason.

I am an anarchist (the capitalist sort, not the weird "we're really liberals" socialist one) and I don't want the government to defend my anything. In any case, who defends what was not in question; I was just pointing out that sustainability is not an issue in a (truly) capitalist society, because the owner of a resource can always decide to limit consumption.