Do not exaggerate this thing.
11 KV has not only triangular shape, but it can be taken horizontally also.
If you take it in a triangular way , only one pole is used/ But if taken in a horizontal plane two poles are used.
But the main question is not of the poles - It is of 1. How many circuit (which depends upon Current which is to be fed) 2. The Insulation Discs (Depending upon the voltage ...11 kv in your case)

Secondly , 440 v line requires 4 conductors to be laid on poles.
The voltage is very low as compared to HV poles. So very small discs are used. that can be embedded on a single pole.

And if you look on the 11 kv poles the size of the discs are bigger. And their numbers increase along with the voltage ratings
as per 2 per phase for 22 kv
3 per phase for 33 kv
so on.
not only this but the design of pole may vary on the basis of current being carried.... if current is large enough... a double circuit is used.
Thus these factors alter the design of poles.

Hope this satisfies you.