And the torque you see at the shaft is reduced by that torque lost to friction in the commutator and bearings...
A rough rule of thumb is usable torque is proportional to current minus no-load current in a simple
DC motor (permanent magnet stator, to be precise).
In theory speed is proportional to voltage at the terminals less IR losses in the windings.
Large well engineered PM DC motors behave close to the theory IMO.