ALMA finds regularly rotating disks at z of 4 to 5 with V/sigma of 7 to 10, as dynamically cold as local spirals, within 1.5 Gyr of the Big Bang (Rizzo 2020; Lelli 2021; Roman-Oliveira 2023). ΛCDM simulations predict V/sigma of 1 to 3 at those epochs, with cold disks emerging only after z of 1 to 2 once merging subsides. Tracer systematics shift population averages but cannot erase the cold settled systems, whose incidence keeps exceeding simulated outliers.
The model assembles disks inside an ongoing bombardment: accretion, mergers, and instabilities stir every early system, so dynamical coldness is a late achievement earned after the violence subsides. A cold disk at z of 4.5 requires hierarchical assembly to have politely skipped a particular galaxy during the epoch when it should be most active.
SCT sets disk kinematics at seeding: a grazing collision deposits its debris with ordered angular momentum J = μ(b × v_rel), and structures condensing from that debris inherit a coherent rotation field rather than acquiring one against turbulence (P31, P32). The centrifugal barrier of the inherited J organizes the gas into a rotating disk from the first dynamical time, so dynamically cold, fast-rotating systems at z of 4 to 5 are the unprocessed birth state, not precocious exceptions. Settledness does not have to be earned because it was deposited.
The population statistics follow. Cold-disk incidence should be highest, not lowest, among early massive systems, because they are closest to their seeding configuration and least processed by subsequent traffic; dispersion grows later where interactions stir the inheritance, inverting the ΛCDM timeline in exactly the direction the data keep moving. The turbulent ALMA subpopulation fits as the secondary modulation: systems whose local environments have already begun decohering the birth rotation (P34 geometry diversity), so the observed mix of cold and turbulent disks maps the processing history, not the formation struggle.
This is the same J inheritance behind morphological maturity at high z, spin-filament alignment, and the merger-fingerprint absence. There is no need to invoke per-galaxy suspensions of hierarchical violence.
The timeline is the kill: SCT requires the cold-disk fraction among massive star-forming galaxies to stay high or rise toward earlier epochs at fixed mass, while ΛCDM requires it to fall steeply. JWST and ALMA cold-disk fraction curves showing coldness systematically increasing toward later times at all masses, with the earliest disks uniformly turbulent at V/sigma of 1 to 3, would falsify inherited rotation as the birth state and restore the assembly-then-settling order.