Ed's method made me think of another way to do it.

Starting with this bottom profile:



Select it and then run Transform > Array > Circular, and pick the center point as the array rotation origin.

Normally Array circular is used for making a circular pattern of shapes, but all it really does is rotate things around the center point, so you can use it combined with the vertical step option inside of it to make a pattern like this:



That does a rotation and a vertical step for each item.

Then window select all those curves and run Construct > Loft to build a surface through them:



- Michael