Due, to know life on the moon there would be nothing to mess with the footprint, but the main reason why these footprints are going to last centuries is because "there is no weather." Since how there is no weather on the moon which means no wind there is no factors that could affect the footprint.
The footprints on the moon's surface left by the Apollo astronauts last for long long time, for centuries, because there is no atmosphere in the moon's surface. As there is no atmosphere in the moon's surface, there is no water and no wind on the moon. So there is no chance of any erosion by wind or water. All the water is present in the frozen form on the moon. Also there is no any volcanic eruption nor any kind of natural forces that will destroy the footprints of the astronaut.
