"In the last case, where thrust equals weight, setting the wing to the zero-lift angle-of-attack yields a steady-state climb regardless of airspeed, so the concept of stall speed becomes meaningless.*"

Sorry, that was a bit sloppy. If thrust=weight, no thrust is available to counteract drag, and so airspeed must be zero in the steady-state case. Angle-of-attack is undefined, so the wing cannot be considered to be stalled. Progressively higher T/W ratios (greater than 1:1) allow for progressively higher airspeeds, with the wing held at the zero-lift angle-of-attack, as the aircraft climbs straight up. Obviously we have abandoned the concept of a 40:1 L/D-- we have shoved the stick forward to unload the wing to zero lift as we climb straight up, so L/D is zero.