Massive fail on the Korea's and China's part with making porn illegal... it's a huge industry and by doing so gave Japan "exclusive rights" to Asian porn along with all that $$$$$.
Piracy may affect sales, but it give av stars more opportunity to be invited to stage events and film ads for gaming products and small non-porn productions all over Asia even if they retire already. Ex: sora aoi, maria ozawa, yui hatano, rola takizawa, and anri okita. There's the dark part of the av industry where some are force to work in the av industry or to film certain extreme scenes. Also, the new and popular replace the old by decreasing their promotions and events. I think more popular idols will transition to av like yua mikami and shoko because good pay and publicity to get more sponsors and sugar bosses. I'm not sure if these are factors to why a lot of av idols decided to retire or they decided it after seeing their friends leaving.