When I post-dived on myself just now, I found a thread about the comedian Har Mar Superstar, who had stepped out of the spotlight himself and was working as a mailman last Christmas season.
Raymond Griffith was nearly as successful as the big four of silent comedy. He quit as soon as sound came in (with one exception). His voice was not suitable for sound, since he had wrecked his vocal cords as a stage actor and couldn’t speak above a whisper. He made only one talkie – All Quiet on the Western Front – where he was only required to whisper.
It’s the one unambiguous example of someone whose voice was not good enough for talkies.
Mary Pickford retired in 1933, four years after winning an Oscar for her first sound film. Her voice wasn’t an issue, but he last three films were flops, so it looks like she just walked away from it.
Sounds like he didn’t really step away, he just couldn’t get a job.
Susan Dey of “The Partridge Family” and “L.A. Law” retired from acting in 2004 at the age of 52.
Sue Lyon (Kubrick’s Lolita) left the movies at age 34 (probably lack of good roles).
Someone told a story on Reddit about working at Hot Topic a few years ago, and a member of a local band that had hit the big time (which s/he refused to name) came in to apply for a Christmastime job. S/he asked why he was doing this, and he said that not only was the band’s popularity declining, but they were planning to disband after their booked tour dates were finished (and they did) and among other things, he wanted to go back to college, another band member had gotten married and they wanted to have children, etc. In short, they were moving on.
Let’s just say having him there was very good for business - and a year or two after the band broke up, HT stopped carrying that band’s t-shirts.
Completely unrelated, but did you ever hear Har Mar Superstar’s cover of Prince’s When You Were Mine?
He didn’t walk away from the business, but Ron Howard had the smarts to realize he wasn’t going to make it as an adult actor (okay, he was 20 when he started playing Richie Cunningham, but that was because he still looked like a teen), or at least realized that he was typecast, and turned to directing and producing, which he is quite good at.