Perhaps it is stashed in a location where it can't be used because it is ergonomically terrible? (Appears so to me at least.) And for the same reason you have not been able to come up with a satisfactory variation.

* Leg corners extending above the seat are suspect

* Narrowing back is the opposite of how most chairs get wider towards the top, where you actually need the support.

* Back appears to angle back too much.

* Reclining is going to generate shear force on the T joint at the bottom of the back sticks...not optimal. Also you are going to get some crazy forces on the mid-joint of the back sticks.

I conclude: it is just for looking at.