They could've worked in cities. Lead-acid batteries, though, have never had the energy/weight ratio necessary for the type of long-range driving necessary outside of highly urbanized areas.
I don't think you can really make any sort of meaningful conclusion from this - rural areas tend to lag in this sort of innovation.
Not developed by my comment is in 1920 you didn't 'need' a car in cities. Since you had street cars. In rural/small town America cars were really useful but electric cars were a non starter.
It's just that fossil oil is - relatively speaking - very cheap compared to other sources.