“The Rambler I owned had a plastic bag that probably held a quart.”
That brings back memories, Triedaq!
My father’s '66 Ford Galaxie 500 (IIRC, 1966 was the first year for Federally-mandated windshield washers) also had a plastic bag hanging in the engine compartment that held–at most–1 qt. On a winter day with lots of salt on the roads, it was possible for me to use up that quantity of WW fluid in just a couple of hours, due to the small size of the reservoir and the fact that the nozzles of those days were not very precise, and tended to just gush fluid.
I also appreciate the very large WW fluid reservoirs on modern cars, and that allows me to go for–maybe a few weeks—during a hard winter before I refill it. Even in the summer, bugs on the windshield cause me to use the fluid often enough that I can’t imagine anyone leaving the fluid in there long enough to develop “slime”.