Aluminium's price fell continuously after the Hall-Héroult process, without a hold-then-collapse plateau

The Hall-Héroult electrolytic process (1886) is often invoked as the canonical case of a radically cheaper extraction method displacing an older one — it is the historical analogy named alongside claim-asteroid-pgm-price-holds-then-collapses, a system-dynamics model predicting that a commodity's price holds near its pre-disruption level until nearly all supply has shifted to the cheaper method, then collapses toward the new cost floor. Checked against the historical record, aluminium does not trace that shape. Per Wikipedia's history of the metal, the price fell continuously as electrolytic capacity scaled: "the price fell to $2 per pound in 1889 and to $0.5 per pound in 1894," down from a reported production cost of about $16/lb in 1884 (Wikipedia gives that figure as a producer's cost, not a market price), two years before the process was invented. No plateau is reported between the process's introduction and the price's decline — the slide runs across the full decade, monotonically, rather than holding and then cliffing.

[unverified-quant — needs primary]. The figures rest on a Tier 4 tertiary source (Wikipedia). Per the vault's sourcing floor, quantitative claims — specific numbers, dates, price points — require a Tier 1–2 primary: a contemporary price series, USGS/Alcoa historical production data, or an economic-history paper. Wikipedia is adequate for locating the claim, not for resting it as verified. Verification routed to question-verify-aluminium-price-history-primary-source.

This is the empirical anchor for claim-cheaper-extraction-disruptions-fall-monotonically-not-hold-then-collapse, and pairs with claim-wrights-law-cost-falls-per-cumulative-production-doubling as the proposed governing mechanism for why the decline is continuous rather than held-then-cliffed.