and thereafter in the age of Koufax and Drysdale. Sandy Koufax couldn't throw a strike for 6 years and thus was not effective until 1961 despite throwing an inning every now and then since 1955.
Sandy's example, along with Gary Peters, Roy Halliday, and many others who didn't learn how to pitch until their mid to late 20, should help us understand how guys like Arrieta can seemingly come out of nowhere to be great relatively older than others.
It's all about the skill of pinpoint control and the knowledge of how to use that control and change of speeds to keep batters off balance.
In retrospect, listening to Vince (the only name i heard besides Vinny from Jerry Doggett in the early years) Scully and the Dodgers on radio might have been more about escape from homework.