Both existed. Very simple film cameras could indeed be fixed at one shutter speed and one aperture, much like disposable cameras. They relied on negative film’s wide exposure latitude, and users often chose film speed to suit conditions, such as slower film for daylight and faster film for indoors.

Other compact cameras were automatic even if they offered no user controls. Many had basic metering and would choose from a limited range of shutter/aperture combinations for you. Some used batteries and simple electronics; others could use a light-sensitive cell and a mechanical linkage to set exposure without conventional electronics.

So if a camera had no settings for the user, that does not necessarily mean exposure was impossible to change. It may have been:

• fully fixed exposure,
• automatically adjusted by simple metering,
• or partly influenced by the film ISO you loaded.

These cameras were designed to be cheap and easy to use, and generally worked best in daylight. Low light or indoor scenes were where their limits became obvious.