Lambda-CDM treats expansion as initial condition without derivation from Einstein field equations

Copernicus replaced ad hoc epicycles with a single orbital geometry that later yielded Newtonian and relativistic derivations. The Einstein-de Sitter framework instead requires an initial expansion rate that diverges at the singularity, with matter and radiation acting only to decelerate. No term in the Friedmann equations generates the present Hubble parameter from first principles.

Hubble 1929 measured recession velocities scaling with distance; Planck 2018 and DESI 2024 report H0 values that differ by 4-6 sigma from early-universe inferences. These tensions arise precisely because the model parameterizes expansion rather than predicting it. Broken symmetry from an off-center observer explains galactic rotation curves in Newtonian gravity; no analogous symmetry reduction accounts for the scale factor in FLRW metrics.

Operationally, surveys must continue fitting separate early- and late-universe H0 anchors. Until a dynamical mechanism replaces the initial-condition dial, parameter estimation remains the sole route to consistency with distance-ladder and CMB data.

Future instruments such as Euclid and Roman will tighten the growth-rate constraint f sigma8 to sub-percent precision by 2030, testing whether any extension can close the gap without new initial-condition tuning.