Bars squeeze the model three ways: mature long bars exist at z of 1 to 3 in disks that should be too hot to host them (Sheth 2008; Melvin 2014), simulations need tuning not to overproduce bars locally, and measured pattern speeds are predominantly fast where dynamical friction against a live CDM halo demands slowdown.
The model's disks settle late, so bars must be late arrivals; and the model's halos are responsive particle media, so bars must brake against them. Early mature bars contradict the first commitment and fast bars the second, leaving tuned stability and convenient merger histories to bridge both gaps.
SCT supplies both missing conditions from machinery already running. The early end is M3: disks are settled from the seeding epoch because their structure is the deposited J inheritance, not a late achievement of dissipative settling (P31, P32), the same seeding-epoch principle behind the morphology stall (recid 117) and the high-z grand-design spirals. A dynamically cold disk at z of 3 is simply a high-J deposit a billion years on, and a cold disk grows its bar on schedule.
The fast end is the M6 corollary: there is no particle halo for the bar to brake against. The dark-matter signature is the coherent mesh contribution to Φ_eff (P50, P52), a field structure rather than a responsive medium of orbiting particles, so the dynamical-friction torque that obliges ΛCDM bars to slow has no counterpart, and bars stay fast for a Hubble time. The two halves are independent SCT consequences meeting in one object: the bar forms early because morphology is inherited, and survives fast because the halo it should have braked against is not made of anything that can absorb its angular momentum. The inheritance formalism is in Paper 5, From Chaos To Corotating Hierarchies, with the superposition mechanics in Paper 6, From Chaos to Cosmic Collisions.
Keystone economy: P31 builds the host, P54 removes the brake. The bar census and the pattern speeds are testing the same two premises from different directions.
Both halves are exposed. JWST and Euclid bar censuses finding the mature-bar population collapsing above z of 2, consistent with late disk settling, would refute the seeded-disk half. Integral-field pattern-speed surveys finding bars predominantly slow, with the deceleration profile dynamical friction against a particle halo predicts, would refute the no-brake half directly and constitute positive evidence for a responsive dark matter medium SCT does not contain.