Benito Mussolini was successfully voted out of office in 1943. Yes, other things happened too, but the electoral defeat was key.
Augusto Pinochet was voted out of office in Chile in 1989.
Frank Bainimarama and Jair Bolsonaro were both voted out of office, and that only happened four years ago.
Is it common? Far from it, and it usually requires more than just votes. But it does work, sometimes; and when it does, it's usually significantly less bloody.