This is a fantastic conceptual point - that the true cost of a system needs to include the infrastructure that creates the trust, and we have a complex and expensive legal, enforcement and legislative system creating the trust in our normal fiat based economy.
However, to be useful, while bitcoin can replace some of parts of this, there is still the need to be able to enforce contracts made using bitcoin, so a bitcoin economy would need to reuse much of that infrastructure.
Besides, it's not particularly relevant, because for most people, escaping the costs of the infrastructure that creates trust in our fiat economy is not practical, while escaping the costs of the infrastructure that creates trust in bitcoin is trivial - just don't use it.
Yes, but the purpose is not to 'escape' the infrastructure costs, but rather to 'optimize' them...by keeping them low. So, in a general sense, self-regulating features of an economy (eg, transparency) create a "remedy" for otherwise more expensive-to-monitor arrangements. By increasing the opporunity set of remedies, your system optimizes to a lower-cost-base. That is to say, a 'remediable' inefficiency is different than one which there is no better option. The idea is that credit cards are a net-postive addition vs cash, because they create benefits to the consumer. These benefits are also the reason why the merchants pay (rents) to the CC companies. The "lost business" would be greater than if they did not exist. But again, here you are seeing the level of CC payments is a function of value added and costs avoided. It is not the case that they are really a measurement of the governance costs of the network (ie, those are at once a subset--anti-fraud--and on the other mostly external and borne by others)
However, to be useful, while bitcoin can replace some of parts of this, there is still the need to be able to enforce contracts made using bitcoin, so a bitcoin economy would need to reuse much of that infrastructure.
Besides, it's not particularly relevant, because for most people, escaping the costs of the infrastructure that creates trust in our fiat economy is not practical, while escaping the costs of the infrastructure that creates trust in bitcoin is trivial - just don't use it.