Wrong on the math and the scale.
Japan has about 63 million women total. Even if we narrow to younger cohorts (~30M as you said), the AV industry churn is insane: 6,000 new debuts per year, thousands active at any time, and cumulative ‘experienced’ actresses hit 150,000 historically according to industry reports. That’s the point — high turnover means far more women cycle through than the snapshot of ‘current active 20-30k’ suggests. Tokyo Reporter and others have cited stats like 1 in 200 Japanese women having appeared in AV. It’s not ‘less than 1%’ in the cultural sense.
Japan produces the most AV content by far — way more titles than the US, with an industrialized, idol-linked system. US has high spending and OnlyFans creators (not all traditional and full-time ‘pornstars’), but Japan leads in volume and normalization. China’s is massive underground (your own 4-10M sex workers stat proves the point on scale elsewhere), but illegal and hidden. Japan’s prostitution is legally a gray area. The law bans sex with actual penetration (penis sticking into the vagina or the ass), but blowjobs and titjobs and similar jobs are not included, therefore you can still get prostitutes giving you BJs legally. Also, Japan has a huge amount of brothels that are highly organized with big and proud storefront advertising their services. In China, brothels are far fewer, mostly hidden, and nowhere near as brazen or openly advertised.
Broader sex industry (AV everything else) revenue estimates go up to tens of billions — not nothing compared to agriculture (~$40B, 1% GDP).
The GDP chart actually proves my point: China has completely overtaken Japan in total economic power, going from a fraction of Japan’s size to over 4x larger in just 30 years. Japan is stagnant while China rises. Stop coping with selective ‘active only’ numbers. Japan’s AV dominance is a known cultural export, not some minor side hustle. Facts.