The fact of the matter is that a higher inductance motor has a lower corner speed and therefore you are more likely to be in the downward torque slope region than the flat region at operating speeds. How that plays out depends a lot on the motor and what it being asked to do. Even two seemingly identically spec'd motors from different suppliers can behave very differently under load.

Having said that, you are right that there is often a big difference between the theoretical and the practical. It all depends on the situation so there is no 'one right answer'. I have some motors that according to their spec sheet should go to 900rpm. In practice I have never been able to get them above 300rpm even on a 48v supply and a range of drivers. I think a lot of people underestimate the impact of inertia and acceleration in their designs. Big leadscrews (20mm+ diameter) of any reasonable length have huge inertia and this is rarely factored in most designs leading to stalling and/or lost steps well below the revs that might have been expected. Of course, turning down the acceleration may allow you to creep up on those speeds... The other key issue is resonance. Most designs have no idea of their resonant frequency (its not easy to work out) and often a motor will stall out well below the expected revs simply because torque has vanished at that point and all the power is being absorbed by the resonance. Adding damping mass to the motor shaft can, non-intuitively, increase the maximum revs or sometimes lightly gearing the motor (1.1:1 say) to allow it to turn slightly slower can produce a better overall result without unduly affecting other parameters.