The AstroForge PGM model's price-holds mechanism is a stated modeling assumption — the market price stays anchored to terrestrial supply cost as long as any terrestrial supply remains — not derived from an independent equilibrium argument

claim-asteroid-pgm-price-holds-then-collapses already names the mechanism "deployment lag": price holds near the terrestrial level, then collapses once off-world supply displaces the last of it. The paper's own text (Nachtrieb & Smith, arXiv:2607.06806) states this directly as a modeling premise, not as something derived from a market-clearing proof: once low-cost asteroid supply is competitive, growing supply "will indeed start to reduce prices," but the market price is held up by whichever terrestrial source remains cheapest, staying high enough for asteroid mining to keep healthy margins until terrestrial supply is essentially gone from the market. Because reserves off-world are treated as effectively unlimited, investment can keep growing on that margin all the way to the point of near-total displacement.

The distinction matters for how much weight the model's prediction can bear: the hold is built into the model's pricing rule (a floor set by the cheapest remaining terrestrial source), not an emergent consequence of a competitive-equilibrium argument the paper proves independently. A model can be internally consistent and still be assuming its own headline result.

Provenance: source_url: https://arxiv.org/pdf/2607.06806; source_author: Robert T. Nachtrieb and Steven J. Smith; source_date: 2026-07-07 (v1); source_tier: 1. Verification of the underlying stock-flow equations that implement this assumption remains open at question-verify-astroforge-pgm-model-dynamics (the ancillary AstroForge_v5.mdl file was located but only readable as an AI paraphrase, not verbatim text).