Given that the set designer was trying for a setting in the past, the Rinso box was correct to establish an earlier time. Did you know that when the Bendix Home Laundry was invented and, indeed, into the early 50s, soap was the only available surfactant for laundry, suds and all? Coping with suds and soap curd in the tiny cylinder of the Bendix was one of its great handicaps because in a wringer washer, the clothing was lifted out of the soapy water instead of having it drained away around and through them.
By the time the Maytag automatic appeared, they only recommended synthetic detergent because an automatic could not be taken apart like a wringer washer to clean away deposits left behind by soap and the Maytag had tubs inside of tubs like those nesting Russian matryoshka dolls.
BTW, on the channel next to where Mommie Dearest was being shown, Psycho was airing. I thought how close the subject matter was on the adjacent channels.