Internally driven secular evolution in disk galaxies (bar-driven gas inflow, pseudo-bulge growth, gradual reshaping) appears to slow or saturate at late times (Kormendy & Kennicutt 2004; Sellwood 2014; Debattista & Sellwood 2000). Many galaxies show only modest ongoing structural change, despite ΛCDM-based simulations predicting prolonged bar growth, strong angular-momentum transfer to dark halos, and continued bulge building.
The standard model has CDM-dominated halos providing strong dynamical friction and long-term bar-halo coupling that should drive continuous secular evolution. The observed slowdown demands galaxies to be more baryon-dominated than abundance-matching predicts, which conflicts with standard dark-matter-content estimates.
SCT replaces the hot-dense-center with a superluminal collision and the thermalized debris field. From this single change, galaxy structure inherited at cascade-seeding (P22, P25, P31, P32) is preserved across cosmic time by Noether-protected angular momentum conservation. Bars, pseudo-bulges, and disk shapes set at cascade-deposition do not need to evolve further through hierarchical mechanisms because their J inheritance is conserved.
Reduced halo-disk coupling from gravitational superposition (P50, P51, P52, P54) is the mechanical reason the secular evolution slows: the Φ_mesh-based effective halo does not provide the strong dynamical friction that a particle CDM halo would. Without dense CDM particles to couple to, bars don't transfer angular momentum efficiently to a halo, so they don't slow down rapidly. Pseudo-bulges don't accrete continuously from bar-driven gas inflow because the secular gas-driving mechanism is weakened by the reduced coupling.
Pre-existing matter from prior cycles (P25) gives gentler gas-accretion histories than ΛCDM hierarchical-assembly predicts, further reducing the secular-driving fuel. Predicted secular evolution proceeds 30 to 70% slower at z = 0.5 to 2 than ΛCDM standard expectations. The same M3 + M6 framework that produces the bulge-disk decoupling (recid 114), the morphology evolution stall (recid 117), and the bar-fraction puzzle (recid 118) accounts for the secular slowdown. Galaxies are baryon-dominated effectively because the CDM halo is replaced by the coherent Φ_mesh contribution.
If precision JWST + Euclid + Roman secular-evolution surveys find galaxies showing the strong secular evolution ΛCDM predicts (continuous bar growth and pseudo-bulge build-up at the standard rate, with bar-halo coupling at the CDM-particle expected amplitude), the M3 + M6 reduced-coupling explanation is refuted. The signature SCT prediction is 30 to 70% slower secular evolution from cascade-inherited stable structures.