As a result, they have lost the parachute they once had in times of financial setback—a back-up earner (usually Mom) who could go into the workforce if the primary earner got laid off or fell sick.

因此，它们已经失去了在经济萧条时期曾经持有的“保护伞”——一个后备挣钱者（通常是母亲），她可以在主要挣钱者失业或者病倒的时候出去工作。