Consistency in statistical averages over a long period of time does not automatically determine individual greatness, especially not all-time greatness. Yes, a player can achieve regularly high marks throughout their tenured career, but Aaron only achieved one World Series victory, so does his consistency necessarily mean he went above and beyond the performances of his contemporaries? Additionally, if someone had consistently high numbers over, say, 18 seasons instead of 23, does that take him out of the GOAT conversation? Babe Ruth does not even reach the top 50 all-time games played list, so is he, along with many other amazing players, out of the running?
The definition for greatness as well as consistency are vague here, and the jump between the two is inherently illogical.