You have actually identified a real issue for these car makers that many are concerned about.
In Japan, electric motorcycles have become quite common. A study of the increased accident/death rates of these quiet electic motorcycle drivers over gas powered motorcycles concluded that automobile drivers could not hear the electic bikes. As a result, the electice bikes were hit more frequently by cars.
They are trying to manufacture sound for these electric motorcycles.
Very similiar issue is the synthetic sound of expensive digital cameras. When first produced, they made no sound and people couldn’t tell they snapped a picture. So, the camera makers added a faux sound.
I think people really do use all of their senses without even knowing it. A quiet car can very well be dangerous to cyclist.