Neptune Bob:
The entry of women into the workplace had a lot to do with it- not only did men have to share some housework (though typically, it was the very least amount they could get away with), the woman couldn't devote 24/7 to the job, the way she had previously. Also, having a "maid" (middle-class parlance for a housemaid) became nearly impossible; there were better jobs available for the women who had formerly done that work, plus wages had risen. So, wives had much less time and help than formerly had been the case. A dishwasher was an enormous boon under the circumstances, as were automatic washers and dryers- these appliances were no longer luxuries, they were the difference between getting the job done, and not getting it done.