Why do wombat incisor teeth continuously grow like rodents?

Due to significant wear and tear from chewing tough, abrasive grasses and roots

Wombats possess continuously growing incisor teeth, a physiological feature they share with rodents. This constant eruption mechanism is an essential evolutionary response to their diet, which consists primarily of tough, abrasive plant matter like grasses and roots. The physical action of masticating this material causes severe and constant wear on the enamel of the incisors. If the teeth did not replace the material worn away through continuous growth, the wombat would rapidly lose its ability to effectively graze and process food, ultimately leading to starvation. This dental adaptation ensures the longevity of their primary tools for acquiring sustenance.