This brand still existed into the 1970's, advertising under the same name! I assume in the 1940's, the modern slang was not in common use. Some word origin sites say "poo" arose in the 1950's. By the 1970's, this branding must have become problematic!
Nothing wrong with the product, as far as I know. Similar dry shampoos can be purchased today, under rather different branding.
In the past, you had to hand draw promotional pictures to convey the marketing message. Nowadays, you just generate the same pictures with AI. Either way, the pictures and stories are equally fake.
I guess the biggest difference is the amount of time a human spent with the picture. Nowadays, some marketing pictures clearly went through exactly zero seconds of quality control.