In image 1 you have a curve with the pivot point far below it. When revolved, it gives you a shape similar to what you are trying to achieve. (image 2)

In image 3, you have the same curve that has the pivot point very close to it. This produces the shape you see in image 4.

So as you can see, the farther away the pivot point is, the more geometry you'll end up having.

How do you change the pivot point? Select your object, select the translate (move) tool in Maya, press the INSERT button on your KEYBOARD, grab the pivot thingamajigger and move it where ever you want, press the INSERT key again.