Exactly, like how "mindful" and "demure" recently became more popular for seemingly no reason. Humans do this all the time.
And language in general stagnates and shrinks in vocabulary over time ( https://evoandproud.blogspot.com/2019/09/why-is-vocabulary-s... ). (Link that ChatGPT helped me find :P) I think AI will increase the average persons vocabulary, since it appears to in general be better/more professionally written than a lot of what the average person is exposed to online.
But also, words and phrases do become popular among humans, right? It would be a shame if AI caused the language to get more stagnant, as keeping up with which phrases are popular get you labeled as an AI.