Why Japan could not simply swap carrier conversion hulls

Why did Japan not convert Amagi-class hulls three and four, Atago and Takao, instead of Akagi and Kaga?

Because work already completed on the hulls constrained the choice; an earlier administrative pause would have been needed to preserve the alternative.

Work already carried out on the alternative hulls had closed the conversion option. A pause earlier in the decision could have preserved room to reconsider. The discussion uses the example to explain why administrative speed can have costs: acting promptly may commit an organization before it understands the consequences. Waiting too long can also cause trouble, so the argument is for enough time to correct a decision before it becomes irreversible.