Why do sea stacks eventually disappear?

Sea stacks are isolated pinnacles of rock that form as remnants of coastal landforms on a wave-cut platform. They do not disappear due to a single event, but rather because erosion is a continuous, ongoing process.1

As waves constantly batter the coastline, the same forces that created the stack—wave abrasion and the collapse of weaker rock—continue to act upon it. Because these features are exposed to persistent wave energy, they are eventually worn down completely, leaving no trace of their former existence. The rate at which this occurs depends on the specific type of rock and the intensity of the wave energy at that site.12