Santiago's Metro network is undergoing its largest expansion since 1975 through three new lines—L7, L8, and L9—announced in two waves (2017 and 2018) and opening on staggered timelines through 2033. This multi-cohort rollout is a setting where conventional two-way fixed-effects (TWFE) designs are known to misestimate treatment effects through negative-weighting bias, while static net-present-value rules ignore the option value of deferring irreversible construction under uncertainty. We address both using a hexagon-semester panel (2010S1–2025S2; N = 67,072) and a hedonic cross-section (N = 647,849) built from Chile's SII cadastre and F2890 registry, combining Callaway and Sant'Anna's group-time estimator with a linear-programming HonestDiD sensitivity analysis and a real-options investment-timing model calibrated on the panel's own empirical volatility and drift. We find a baseline pooled hedonic capitalization elasticity of +5.9% with respect to gravity accessibility, cohort-specific dynamics a pooled TWFE obscures, a non-monotonic anticipatory uplift across socioeconomic-disadvantage quintiles, and a capitalized land-value gain 1.8 times below the real-options investment trigger—indicating anticipated capitalization alone does not yet clear the option-adjusted threshold for accelerating construction, without speaking to the corridor's broader social return. The results caution against treating land value capture as a substitute, rather than a complement, to social cost–benefit justification for transit megaprojects.