A salary can be instrumental in breaking the exclusive association of women with domestic labor and child care by attracting men into the home. Sheer altruism won't motivate many men. A salary changes the situation and acts as a definite drawing card. Bingo, prestige rises. A second consequence of the lack of independent income is that women who remain in the home are robbed of the joys of providing for their families.
Daddy is the provider and at times the nurturer.
Mother is to be confined to the role of nurturer, a role which has its own satisfactions but which is undeniably limiting. A salary provides the solution. Money doesn't necessarily buy freedom. Freedom can be achieved without money or so they tell us. Nevertheless, the suggestion is made that there is for the average person in our materialistic world a connection between the two.