The truth about Japan's lack of sexually active men is simple to understand: the more limited your social space, the harder people fight for those spaces, to the point that most people can't compete; those who cannot compete become "beautiful ones", or what's known in Japan as "herbivore men." There was an experiment named "The Mouse Utopia" which showed a sped-up version of this phenomenon, you can watch it here:
https://www.youtube.com/watch?v=0Z760XNy4VM The mice in this video which gave up their sexuality focused almost solely on maintenance of their appearance; the key here is that they neglect to have families, which is among the parallels with herbivore men. Consider, now, the appearances of herbivore men:
Some Western examples:
It's not just Japan; you can find this in any country where social space is becoming increasingly limited. It's noticeable over here in the West as well with the rise of e.g. feminism and mgtow, and falling birthrates. But Japan appears to be in the most advanced stage of this. Of course, Japan is well known for its severely limited space physically, but this translates to limited social space as well, especially considering how machines do more and more of the work which would otherwise necessitate people (i.e. give them a space in society), and now consider the dawn of sex bots which would weaken the social power of women, given enough time and innovation, and thus tighten the space for them as well--but likewise, the lack of participating men naturally lends itself to the rise of non-participating women, for women have to compete with one another for the remaining participating men. Notice that this is primarily occurring in the most advanced nations. Meanwhile, the sex drives of the worst nations flourish--esp. noticeable with the middle-eastern "refugees" and their rapefest as of late. And of course, their appearances are nothing to envy.
The problem is not limited geography--this can be an issue, particularly considering Japan, but seeing as there's plenty of empty physical space in, say, America, and yet still we are seeing a rise of the beautiful ones, it becomes clear that the true issue here is the lack of social expansion--this is becoming increasingly true for the latest generations, they just don't have anywhere they need to be for there's nobody who wants them and it shows with their ideological leanings, e.g. SJWs and Bernie supporters (socialists, i.e. exacerbators.) If you understand how the state impedes market activity which directly translates to slower business creation and worse business performance, you will understand how a state which grows its power lends itself to the issue: when you're paying the cost of high taxes and the watering down of your purchasing power a la inflation, you're left with less for yourself, and this makes it difficult to produce new businesses, in other words to create more social space; allotting people more of their own earnings would allow people the time, resources, energy and motivation to expand and procreate. The alternative resolution to this issue is, instead of increasing the amount of social space, you decrease the amount of people competing for those spaces: enter, war. But that doesn't help anybody at best and just sets everyone back at worst (especially consider its cost not just in human lives but the financial expenses involved per se), it's more like a violent expulsion of the at-present non-necessary members of society than a beneficial solution to the core issue, being lack of social expansion. Through improvements to our rate of social expansion, those non-desired members of society become desired once again (well, except for the violent criminals, they'll still be non-desired) as there is eventually a surplus of social space to fill, rather than competition for limited and shrinking space--a golden age, totally opposite to what we have today.
