The real difficulty for the Japanese was that they had enormous trouble with the construction of really high powered engines. This was mainly a function of supply difficulties, and of production pressures and the attendant shortcuts, but Japanese aircraft engines, especially those used in the 1943 and later designs had simply awful reliability. The further you get into the war, the worse this becomes.
This problem was made even worse by the "mindset" of the Japanese maintenance system. While U.S. practice was to strip every washer off of a plane that had been written off, the Japanese did not follow this practice. This may have had something to do with the horrific losses that scythed through the mechanics ranks, especially of the IJN, but also of the IJAAF. One of the things that U.S. support forces were constantly surprised by was the number of aircraft that the Japanese would have in their "total loss" junkyards that could quickly be brought back into action by taking a part or two (literally) off of the plane right next to the "dead" one, bolting them in place, and hitting the starter. This is all the more surprising when you look at the brilliance that the Japanese showed in making do as the Americans closed in for the kill, but it happened virtually every time the Americans came across Japanese airfields.
While the Japanese did have some exceptional pilots who survived the war, the overwhelming majority did not. This was, in part, due to the Japanese practice (similar to that of the Luftwaffe) of keeping pilots out on the cutting edge for WAY too long, but it was mainly due to the fact that there was a dramatic drop-off in pilot quality throughout the ranks as the war progressed. Pilots who would have never been allowed to climb into a cockpit without an instructor in 1942 were flight leaders in late 1944. With a few brilliant pilots and a gaggle of amateurs flying with them, the cream of the Japanese pilot corps was simply obliterated by the onslaught of meticulously trained and robustly equipped American naval aviators. Even the best pilot has a limited life span when confronted by four or five men who are his near equal, all of whom are flying more survivable aircraft and who are trained to fight as a team. That Sakai and any of his brethren survived the war was miraculous. The chances of them making it into mid 1946 would have be miniscule.
Probably greedy of me to ask for more, but this fascinates me. What is up with that (both the bad mechanical practices and the bad pilot practices)?
Is there a good book or two to consult on this? Or more?