The cheaper joysticks use potentiometers. There's a little tiny metal contact sliding along a resistance track. Dirt, water, age and electrical noise will all cause problems in the long term.
Expensive joysticks use hall effect sensors. They sense the rotation of a magnet without touching it. They never wear out and dirt and water don't affect the magnetic signal. If you can find one under $300 you are doing well. However some single-axis controls such as the throttle on an electric bike use the same technology and they are relatively cheap.