to sign up. They simply allowed anyone who wanted to join, regardless of age, come along. There were likely thousands more with the ability who had no interest in becoming AS because of what AS stand for in the WOT world. The women drawn to the AS system are in no way a representative sample of all WOT women, thus until they begin recruitment like the Asha'man there will always be a skewed sample in the White Tower.

I agree with Fionwe that RJ may well have done this very deliberately as he did so often throughout the series ... the man almost never made a "mistake" like this without a reason. Certainly some of his explanations were thin, but he always had one when someone asked.