Voice acting (dubbing) is acting, which is a "high form of labor". In some languages/countries, most of the dubbing is performed by a few extremely good voice actors.
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.
they wont replace voice actors for that. Rather it will replace voice actors for niche languages for niche content. Just like AI generated images doesnt replace artists working on the latest pixar movie but rather lets some small blog ad an image they would never had otherwise.
But there's a lot of people who have been working as voice actors for small/medium visibility content. Toothpaste ads, Kickstarter promo videos, corporate training videos, mid-range video games... a chunk of that is going away, and it's going to hurt a bunch of people who were previously able to make a decent living off it without being a star.