This is not the case in my world. I know many successful people, including lawyers who have practiced law for almost 50 years, who swear far more than people *significantly* younger.
I don't know what world you live on, but in my little slice of Canada, we fucking swear.
From all the blue collar workers, such as myself, up to all the cops, lawyers, doctors, nurses, teachers, etc. Doesn't matter the age or profession, swearing is commonplace.
Are there some that don't swear as much? Of course. But even my ultra evangelical boss is known to throw a fuck around, when the occasion calls.