Long Term Defense Issue in the Future

ALSO, I question whether Japan would be a threat even if they did manage to rise up, get the economy buzzing again, get their citizens horny and breeding again, finally kick the Americans out and build up an impressive military. I really think that the hatred between modern day Japan and China is vastly exaggerated. Sure, there are ultra nationalists on both sides that make the situation look bad, but the average citizen doesn't really care. In the end they are more interested in making money through economic cooperation. You don't ruin that by launching a pointless invasion that will also be decried by the rest of the world, causing even more economic hurt via sanctions.

In the age of globalism, people frequently underestimate just how much it would take to provoke a major war between two major powers.

war between two wealthy or powerful states nowadays is almost impossible. war by proxy is the way to go baby.
Japan is not doing itself a favour by alienating from China, luckily the new PM is very friendly to China so I am lookin forward to see the the relationship between two countries improve.
the fact that the US has their military in Japan isnt necessarily a bad thing for China, i rather have a Japan that is being checked by the US than a politically and militarily independent Japan.
younger Japanese nowadays prolly know less about their country than some of us (none Japanese) do. but again, it was the same case before the Meiji restoration came along. so if some huge political change happens in Japan you can expect that ultra-nationalist feeling to revitalize again. this is the problem with this nation, they are always on the extremes, either they care too much, or not at all.

Maybe it's asking too much for the historical animosity between the two countries to die down to the level of "friendly rivalry" like the amazing case of Western Europe, but relations have been pretty good since the war shrine visiting Koizumi's reign ended.

as a chinese (or hk), i really want to see the gender ratios return to a healthy balance.
as for demographic growth, holding chinese at the current population is alright for another while