Electric motors are significantly better at the requirement that matters: endurance.

Sure it takes a bigger motor to produce the same torque, but speed and precision are actually the strengths of electric motors. The fundamental problem with them is that reducers are not impact resistant and they have internal inertia, which is something muscles do not have. Another problem is building actuators with multiple degrees of freedom. The ideal configuration for legs is a ball joint, not two consecutive rotary joints.