Why there is no East Asian great replacement theory?

East asian countries have even lower birthrates way below replacement rate, but no one says that this is something that is self-inflicted and a natural part of being a developed country. I do understand that they have low immigration rates (yet) but great replacement theorists say that feminist propaganda, emancipation, higher % of women in work field is something that was forced on them by foreign influence (illuminati, jews and other bullshit).