Oh, it can fail. Mine failed after while of making noise with the clutch pedal pressed in. Took the clutch release arm and pressure plate with it when it went. The throwout bearing was in three pieces when it was removed from the car.
It could very well be the throwout bearing, but it could also be a transmission bearing. When you are not moving, have the clutch pedal released and the transmission in neutral, the input shaft and idler shaft are still rotating at engine speed. When you push in the clutch pedal to disengage the clutch, the input shaft is disconnected from the engine and will stop turning.
It could be either the throwout bearing or a transmission bearing.