Why the efficiency of the Induction motor is less compared to transformer?

Induction motor and Transformer operates on the same principle that power is transferred to secondary by mutual induction. But in transformer, flux will be traveled from primary to secondary winding through the core of the transformer. In induction motor flux travels from stator to rotor through the air gap. Therefore power factor will be less for induction motor compared to transformer which also results in less efficiency for induction motor compared to transformer.