Mike Royko comes to mind.
I've read the same thing about newspapers in England. There were always upper class folks hired directly as reporters -- Winston Churchill for one -- but a lot of the reporters started out as errand boys in the print shop, or mail clerks in the office. It was very possible for a 15 year old school drop out who went to work for a paper to become a reporter, and not impossible for one to end their career as an editor. But by the 1970s, new reporters came exclusively from the ranks of university graduates.