There are lots of reasons, like they are very difficult or impossible to seal well to the weather,they are dangerous that you may be hit by some going the other way. In the rare cases they are used they either have glass in them so you can see someone coming, or they don’t fill the opening so you can see over or under them, or they are rarely used and mostly left open. Double saloon/cafe doors are a crushing hazard if you get your fingers stuck between them as they close. This is true of any double door but the chances of injury are much higher with the saloon doors. Basically the minimal benefit of not having to pull the door open in one direction of travel is massively outweighed by major practical problems and safety hazards. 

To design a door that will swing both ways means there will be no stop on the door jam. Stopping the door at the point that it is closed is only one part of the issue for doors that swing both ways. Sealing the door is a secondary issue and the stop or door stop provides a visible seal around the door and diminishes the air that leaks around the door. In the case of a door made for a room where some privacy is expected such as a bathroom, the door stop prevents voyeurs from looking through the space that would be required for the door to swing both ways.

2 way doors are possible with the right hinges, but also this will require an equal amount of clearance for the door to swing in both directions. This consumes floor space on one side that would not typically be needed. And finally in high traffic areas, and with a 2-way door that does not have a large window to see through, this will present a risk to two people arriving at the same time and smacking each other in the face as they collide with the door between them.

One of the most popular 2-direction door is swing door with 180 degree opening , it's also one of the best selling doors from TSTC .