The strongest argument against Bitcoin would be a fiat system that actually worked

Most Bitcoin discussions start from the assumption that fiat currencies are fundamentally broken. But let us stop and steelman fiat, for once.

A well-functioning fiat system has real advantages. Centralized monetary systems are more resource-efficient, easier to coordinate, and can respond quickly during crises. In theory, they can provide stable purchasing power, fast payments, financial stability, and predictable rules without needing a decentralized alternative.

The problem seems less about the design itself and more about sustaining discipline over long periods of time. Monetary systems are run by people and institutions under political and economic pressure. Historically, debasement, monetary expansion, and rule changes tend to appear repeatedly during periods of stress.

Bitcoin seems to start from a different assumption. Fiat assumes long-term discipline from people in power. Bitcoin assumes that discipline eventually fails.

Do you think that is a fair steelman of both systems, or is there an important advantage or weakness on either side that this framing misses?