Why won’t this motor turn?

Ideal H-bridge and DC motor at steady state. R = 8 Ω; Ke = Kt = 0.04 in SI units; viscous friction b = 0.0002 N·m·s/rad. U = RI + Keω and KtI = bω + resisting torque, with stall when torque is insufficient. Current is shown as a magnitude; A − B voltage and speed are signed. PWM is averaged. Inductance, startup, switching, regeneration, bridge voltage drops and heating are excluded. This does not reproduce the L298 or a commercial motor.