Mrs. Tzippi:
(Let me first say up front I do have some negius, as I am well aware of Moshe’s work in the field).
The point being made (which is a good one) was that assuming the girl wants to marry a learning boy, she is in a better “position” (and therefore brings more to the table) if she gets married later than earlier (as she will have more saved up). Its only the “crisis” that makes people (read: boys & their mothers) think that a younger 19 year old girl is better for them than a more settled (and more able to support) woman.
Your point is a different discussion: Why are the girls insisting on someone who will B’Davka NOT support THEM!?
(as required by the kesubah, as many have pointed out)