In the US, most (all?) convictions are public record, and the ones that aren't public record can still be found by employers who retain background check companies.

Such as ? Employers demanding a paper from the police listing all your convictions is everywhere in Western Europe. Even a traffic-related conviction can be a problem. This is also something that comes up when talking to homeless in the Netherlands. Tldr: conviction for something done on the job (can be traffic accident on the way home) -> fired and significant money -> no new job because "strafblad" -> poverty -> homeless