What Type of Electric Motor Do Servo's Use?

I've been looking up electromagnetics, is it the voltage of the current running through the coil which determines the amount of load the servo can carry, or is it the strength of the magnet?

I cant believe how primitive the motor is, it almost seems medieval, i was hoping for some serious engineering in there lol

So its basically hundreds of fine wires of copper coiled with magnets surrounding it ... ?