One useful metric for valuing a system or network is how much effort is required to defend it. In free markets there’s a selective pressure for stability and durability.

For example for a company to maintain or increase its value it must maintain demand for its products or services while competing against other providers but also fighting internal problems like bureaucracy, incompetence, corruption, etc.

A fiat currency is similar in that it must avoid depreciation relative to other currencies (competitors) as well as fraud (bank corruption, inflation, etc.). The sheer amount of people it takes to keep fiat rails working despite all the incentives for them to cheat combined with lack of transparency by design make it incredibly hard to defend.

Compare that with bitcoin that was designed to be transparent and incorruptible from the beginning. There’s an asymmetry between attacking and defending it so that corrupting the system is orders of magnitude harder than defending. It’s not perfect, but it’s better than the alternatives.