If last 3 owners got rid of the car withing 12 months, why wouldn't you want to do that too?
Usually (but not always) a car that had several owners have something that made their owners not enjoying owning them, so they got rid of it before usually people do. For example: the car wears the tires very quickly, fuel consumption is much higher than expected, has several hidden issues that would cost expensive to fix (usually this is the most often reason). All these factors lead to the owner to sell the car prematurely.
Several owners, several abuses
Even if the car is otherwise good, different drivers may inflict different abuses to the car. Most people keep the car well but have one or more specific points that is overlooked, since nobody is perfect and usually those points vary from people to people. E.g. First owner keep the car well but drove the car on the track, second never drove on the track, but the skipped some oil changes, third never drove in the track neither skipped oil changes, but the streets of his neighborhood were poor so the suspension suffered.