I thought about the cars my parents owned and that I owned that had vacuum wipers. My Dad’s 1939 Chevrolet, his 1947 Dodge, 1949 Dodge, 1954 Buick and 1960 Rambler had vacuum wipers. My 1947 Pontiac, 1955 Pontiac, 1954 Buick 1965 Rambler Classis 550,1950 Chevrolet pickup truck and my 1968 AMC Javelin had vacuum wipers.
Interestingly, Chrysler and AMC put electric wipers on the higher trim line. My Dad’s 1947 Dodge was the lower trim line (the Deluxe), while my upper trim line 1948 Dodge (the Custom) had electric wipers. The 1949 Dodge Meadowbrook (lower trim line) had vacuum wipers while the higher trim line (the Coronet) had electric wipers. The same was true with AMC products. Why it was cheaper to put in vacuum wipers and have a vacuum booster section on the fuel pump as opposed to having electric wipers with a single diaphragm fuel pump is a mystery to me. My 1950 Chevrolet pickup truck didn’t even have a vacuum booster on the fuel pump–the wipers ran directly off the manifold. The wipers on this truck were interval wipers- they only wiped the windshield during the interval that I released the accelerator.
I know that electric wipers were available before WW II. My Dad had a 1940 Chrysler that had electric wipers.