Japanese training was extreme before, and during the early years of the war. It was brutal beyond belief and only a very small % of cadets graduated. At the start of the Pacific War most Japanese active pilots had two years of training plus up to five years of active combat service in China with thousands of flight hours logged.
They expected a quickie too. Thus they had no way to sustain a credible training program during the war, which they certainly needed after Midway. Nor did they have the fuel or industry to win a war of attrition. Most of all after the outstanding talent they started the war with eventually got kilt.
The war in the far east was a water war. A "Naval War". Whatever you want to call it. The majority of shipping interdiction in the Atlantic was done by submarine due to the lack of basing and aircraft capable of the extreme distances. I'd say the Japs got very good at it cause they had a good platform, excellent initial training and pilots, and a whole lot of targets in the first years of war with CVs and land bases dispersed to cover the hunting grounds. Dont forget Germany was considered the greater threat and the majority of allied assets went to the ETO in the first few years.
Sometimes it seems like the entire German military had Hitlers phobia about water. Even the brave submariners died in vain cause Hitler wouldnt give priority to new boat designs. The Stuka was a good anti-ship design but was the Luftwaffe really trained and motivated to fight a shipping war? No they werent! Even their convoy search airframes werent used for what they were supposed to do. Often they were assigned other duties. And Hitler never really saw it, or didnt want to see it, how close they were to starving England into making hard decisions.
In short anti-shipping operations just wasnt the priority of the Luftwaffe that it was with the IJN or IJAAF. Even with identical platforms could ANY air force really compare with the Japs until after '42 in anti-shipping OPs?