Even Marx was forced to admit that workers were not being paid at subsistence levels, and that capitalism led to a rising standard of living for workers. So in order to save his theory, he redefined the concept of subsistence.
The Euro Shows That a Fiat Money System Is More Expensive than We Thought
A traditional argument for unbacked fiat money was based on the idea it was less-costly to produce fiat money than gold or silver. This cost savings could then enrich society overall. But recent data suggests this isn't true.