I think nowadays such jobs have strict Health and Safety rules, to minimize any risk on the job and protect their health, especially since someone working too long could create dangerous risks for everybody, and since for many such jobs it's actually hard to find skilled, experienced workers, so employers take care of those they already have, since accidents are bad for everybody, including the company.
Meanwhile with mangaka it's like "Health, who cares? Can always go to hospital" Or at least it used to be, seems to be slowly changing. Since it's a "safe job", it has unsafe practices with nobody caring.