Answer:
There are two important reasons for that. One reason is that after the Pearl Harbor attack of December 7, 1941, the United States and the British high commands started to plan a strategy to follow in the first phases of the war; they had to prepare a counterstrike and next actions to face the Japanese in the ocean, while guaranteeing lines of communication between the US and Australia and readiness to defend the US continental territory. The other reason was related to technical possibilities of available aircraft, which lacked enough range to bomb the main Japanese islands, such an action required planning and time.
Step-by-step explanation: