We don’t really need to look into his games.
In three years, he pitched 524 innings (16th most in MLB), had a 3.48 ERA (31st in MLB for 300 inning minimum) but was only credited with 25 wins (53rd most in MLB). This tells us he pitched slot, didn’t give you a lot of runs, but was still rarely credited with a win. Heck, Tony Gonsolin had more wins despite pitching 260 fewer innings. Alek Manoah had more wins despite pitching fewer innings with a higher ERA.
And the reasons are most likely the obvious ones - lack of run support or blown leads by the bullpen. Poor defense and unearned runs could be another culprit. And these three primary causes for his lack of wins are all not factors Montgomery can control. Those are Outside Factors.
Yet when we look at his wins solely, we hold these outside factors against him…