Biological exos matter most when ordinary replacement becomes expensive. In well-supplied colonies, they can look optional or even fussy. Under scarcity, their value becomes obvious. Growth is sometimes easier than import, and adaptation is sometimes cheaper than precise reconstruction.
This does not mean exos simply bloom on command. They still require discipline, local chemistry, and environmental control. What changes during scarcity is the economic logic. A colony that cannot count on rapid resupply begins to prefer structures that can be coaxed, renewed, and stabilized from conditions already present.
For the Children of Luna, that shifts repair culture as well. Maintenance becomes less about swapping parts and more about steering growth, constraining variation, and preserving continuity through patient cultivation. The result can look less industrial than conventional machine care, but it often proves more survivable.
Scarcity is where the exo stops looking like a fascinating option and starts looking like a rational technology of endurance.