User blog comment:Zathronas/Analysis by an author: Dust secrets/@comment-78.42.186.25-20140823134926/@comment-24218038-20140824004739

I imagine they don't have access to dust. And I know that those who are trained to use semblance are few and far between.

We see them often because the story is taking place in a school that trains people to use semblance.