Just my observation--in our area. When they started the elder arrangement, more men became interested in becoming witnesses as that gave them the chance to attain a position of importance. Often, UBM's decided to join their wives at the KH. I felt that after the elder arrangement started, the ratio of men to women increased quite a bit--although they were still in the minority.
My father was one of those men. He managed to work his way up to elder although to this day I don't see how he qualified.