Childless is still used - there's simply a difference between the two. Childless = want but can't have children. Childfree = don't want children, don't and won't have them.

Our mothers and grandmothers often didn't think about whether to have children at all; they simply did it. As my mother told me, "It was just what you did." Our current "potential mothers" (by this I assume you mean women, who are much more to the human race and the world at large than simply "potential mothers"?), just as men do, consider what they want for their lives, period, because they're starting to understand having children is one option of many. Many women simply don't want children, regardless of what their career plans are.

(Do you take issue with men considering career/paycheck first, when and if they're trying to decide whether they'd rather have money or be fathers?)