Took our degree in business
As such had to sit through one's share of statistics classes, that was more than enough. *LOL*
As for content of article, yes Alva J. Fisher and his "Thor" electric powered washing machine was the first salvo fired across bow of professional laundresses.
Truth be told first true threat to laundresses came from steam/power commercial laundries. They put out all sorts of marketing and advertising telling housewives they should shun laundresses for their "modern", "hygienic", and "safe" professionally run laundries. Oh there were all sorts of benefits from getting one's laundry back not smelling of kitchen grease to the expert care and attention that only a true professional with training could provide.
Did any of you know the real set back to adoption of both electric washing machines *and* use of commercial laundries in the south was the large supply of "Negro" laundresses?
Quite simply for a host of reasons in early parts of last century until well past WWII African American women had few other choices in occupation. As such commercial laundries found if they tried to lower their prices, so would the laundresses. Big Mommy like her mother, grandmother and great grandmother before her was so used to "cheap" AA labor (and or taking advantage if not down right abusing) she didn't care.
By 1913 Mr. Fisher hired Mrs. Christine McGaffey Frederick one of the first (and leading) home economists. There was a growing trend taking hold on teaching women how to run their homes "scientifically' and efficiently. Much of this was aimed at the rising middle classes where housewives were learning how to deal with running a house with fewer if not no servants.
Mrs. McGaffey Frederick takes two tacks in promoting the Thor washing machine. One geared towards the housewife herself if she were doing the washing without help. The other was addressed to the perhaps better off household who still find (and afford) a laundress.
How expensive were laundresses anyway? Well by the 1910's or so outside of the south (see above) a good washerwoman didn't come cheap.
First one had to either go fetch the woman and or pay her travelling expenses. Since she was going to be on job much of the day you also had to provide lunch and beverages. In many instances these women were mothers and often bought their one (or more) of their small children along (who would have to be fed as well).
Some laundresses were very conscientious others not so much. Some seeking to maximize their time would start your wash, then go over to another home in area to begin someone else's as well. So back and forth she went all day likely much to the annoyance of both women who hired her in first place.
If you look at the chart in OP linked story you see decline of laundresses dropped dramatically in 1940's. That largely could have been attributed to WWII which caused a labor shortage. Women were actively hired for all sorts of jobs that became free due to a shortage of men. Commercial laundries were eager to find laundresses to work in their plants (or anyone else for that matter) to replace men and some women lost to the war effort/military.
By the 1950's where another huge drop occurs, well it would, wouldn't it? The war was over and the boom had begun. Automatic washing machines were rolling off the production lines, and or laundromats opening up.... Plus you had fewer and fewer homes with need or even want of servants.
If there was any special laundering to be one by the 1950's the commercial power laundries, and so called "French Hand Laundries" provided all the services of a laundress. Everything from fine or every day linens, shirts, bundle laundry, bachelor laundry, etc...
All this being said at least here in my neck of the woods there is a demand (however small) for laundresses.
Domestic staffing agencies, want ads, etc... all from time to time advertise for such positions. They are wanting someone to come into a home to do the washing, ironing and perhaps some mending. Work is all done by machine of course, but there you are.
https://www.ziprecruiter.com/Jobs/Laundress
https://www.householdstaffinginternational.com/services/laundress-agency/
https://www.metronewyorkjobs.com/job/detail/28115863/Cook-Housekeeper-Laundress-Weekend
https://housekeeper.com/part-time-laundress-needed-housekeeper-job-new-york-ny
https://books.google.com/books?id=X...onepage&q=Christine McGaffey Frederick&f=true