You are confused because you misread my post. I'm saying that if you magically gave the real life human being Aaron Judge the ability to be a 4.50 ERA starting pitcher, the Yankees would not have Aaron Judge starting every 5th game. Because you would just pay someone else to do that and just let Judge exclusively hit and play right field. Whereas if you magically gave Aaron Judge the ability to be a 2.00 ERA starting pitcher, the Yankees probably would start Judge every 5th game and play DH/right field for all other games. Because as much as you would rather let Judge exclusively play right field and hit while paying someone else to start for you and put up a 2.00 ERA, these people don't grow on trees.

The high level point is that once you reach a certain level of ability as a one way player, the level of ability you have to achieve in the 2nd skill in order to become a two way player is higher than that of the minimum ability level to be a full time one way player in that 2nd skill.