In the short-lived news app Artifact, that was one of my favorite features. It was done on demand, and if a high portion of early viewers asked for a rewritten title, the rewrite would become the default for future viewserves.

In the Artifact implementation, the LLM was specifically prompted by the app to summarize the article with an honest, non-clickbaity title. In Google's case, they claim they are prompting the LLM to title the link to better tempt the searcher to click on it based on what they were searching for. Kind of the opposite. Yes, LLMs could do what you say, but that doesn't seem to be how Google is setting it up.