Ah yes, I often see the ornamental agave in my fatherland pruned this way. Somehow your plants look much larger after the operation. How old are they?
My plant and its subsequent offshoots came from one plant some farmer discarded on the side of the road on the edge of town. I've never given it fertilizer.
As you can see, the "pineapple" as we call it, is not very thick.
You could trim it so it could grow bigger.