I think there are some other influences, too. One is where you live. I remember in England, our organization did not affiliate with Aikikai Hombu because of the cost. There was a lot less discretionary income over there. (I'm in the USA now, and this was 20 years ago.)
Another factor is the going rate. I charge what is the going rate in the area. In fact, there is a karate school in the same facility, and we charge the same as them. So it isn't just aikido.
I did like that thought about yoga teachers explaining how each asana benefits your body. "And now we are going to do irimi nage, which improves the flexibility of the neck."