These things you are saying never happened. Early in baseball history, the soft ball meant that pitchers didn't have to throw as hard for as many pitches. Christy Mathewson's book on pitching talked about maintaining good shape because sometimes you had to "throw as many as 100 pitches to complete a game." 130 didn't need to happen because the ball was put in play much more often, batters were less selective. Later on, as pitchers threw more pitches, many of them *did* hurt their arms. There wasn't this "not have problems" that you think happened. There were tons of problems. Few ever heard of them, though, because there were so many levels of minor leagues that by the time a pitcher made it to the bigs, he had won a war of attrition that proved his arm was one of the few that could handle exceptional workloads. Many more arms burned out in the minors.