For most of baseball history the Win was considered the key metric of a pitcher's success. We now have many more statistics to gauge how effective a pitcher is or was.
Let us be clear: The Win is an important statistic. But it's not the only statistic. A full understanding of a pitcher's career requires more context. As we know, some of the greatest pitchers in baseball history fell short of the 300 Win milestone while some pitchers with 300 Wins are mediocre Hall of Famers.
There are 2 reasons Jim McCormick fell short of 300 Wins:
McCormick was the original "tough luck" pitcher in baseball history.
He pitched 8 of his 10 seasons for terrible teams, only once finishing above 5th (out of 8 teams) in runs scored.
McCormick's team was shutout 39 times while he was on the mound, 33 of those during McCormick's peak from 1879-1884. Only Pud Galvin endured more shutout losses (4 more), and he pitched 5 more seasons and started 200 more games than McCormick.
Bill James' stat waaWL% measures what a pitchers record would be had they played on a league average team. Not only is McCormick's "lost" wins much greater than his peers, he ranks #1 all time among Hall of Fame pitchers in lost wins.
McCormick endured 1.8 shutout losses per 200 innings pitched, more than any of his HOF peers. He also played on fewer .500 teams than any of his Hall of Fame peers and his teams averaged only an 87 OPS+ during his career, the lower than any of his peers.
McCormick retired at age 30 after only 10 seasons while every one of his contemporaries who achieved 300 Wins played much longer, sometimes well into their 30s.
McCormick's wife Jennie was gravely ill with tuberculosis when he retired and she died months later.
McCormick could have held on for several more years at league average as many of his Hall of Fame peers did and compiled more numbers but he retired to care for his wife and tend to his saloon.
McCormick is 7th all time in Wins through age 30.