Why not?
Because if the pot is burnt out there is no voltage change as the wiper moves.
Have you not had potentiometers when adjusting the resistance value goes mental?
Yes but that is not caused by a burned out track. That is caused by dirt causing intermittent contact with the wiper thus connecting it to the wiper at one moment and leaving the wiper unconnected at the next.
With a burnt out track you would expect solid readings of 0 or 1023 for most of the travel until your wiper passed over the burnt bit when the reading will flip to the other extreme.