LLMs aren't going replace all actors or all voice actors just as they won't replace all illustrators or writers.
LLMs provide a certain level of mid/low quality content in nearly all mediums. And given that there many people producing such mid/low quality content today, LLMs will have an impact. LLMs affecting sales writers? Sure (not the best sales writers but the point is sales is mediocre but acceptable is a norm).
And say LLMs specifically. There's good evidence the technology has roughly peaked. That doesn't mean it's impact has peaked but it's indication that "all jobs at risk" might be an exaggeration.