The F-16 is cheaper to maintain because of the economies of scale. If you cant afford a new part for your F-16 there are plenty of junk yards all over the world that you can scavenge from.
The Japanese economy isn't as strong as it seems. It still hasn't been able to address the "Lost Decade", 1991-2000, which was to Japan what the Housing bubble, 2007-?, is to the US.
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LeveragedBuyout can you dig up some research papers on the Japanese Banking? I read somewhere that Japanese Banks were just empty shells. Like the US Banks were in the Financial Crisis, just holding over-priced assets on paper.