The incomparability problem Here is a question that has no clean answer. How do you know whether the architecture you chose was the right one? Not right in the sense of working — most systems work, eventually, after enough effort. Right in the sense of optimal. Right in the sense that the complexity you introduced was warranted by the problem you were solving, and that a simpler approach would have cost more rather than less. The honest answer, in most cases, is that you cannot know. Because the alternative was never built. This is not a gap in the data. It is the mechanism of the problem. Most systems are built only once. There is no second system built with different assumptions, run for five years, and compared on total cost of ownership, ease of change, and operational stability. The counterfactual does not exist. Therefore the cost of the wrong choice — if it was the wrong choice — is permanently invisible. None of this is to say that distributed systems cannot work.…