First, consider timing. ROTK, Water Margin, and Journey to the West predate Dream of the Red Chamber by centuries, being published in late Yuan and early Ming dynasties. Dream of the Red Chamber is a late 18th century Qing dynasty work -- written some 400 years after Three Kingdoms, during an era of Japanese isolationism. So Red Chamber had less time to be absorbed into Japanese popular culture, and was published at a time when Japan was deliberately limiting access of foreigners and foreign culture to Japanese consumers. Including Chinese.

Next, consider subject matter. This is subject-ive, but ROTK and Water Margin focus on civil war and battle and relationships between warriors and their lieges -- topics highly relevant to the Japanese experience. Journey to the West is a Buddhist tale, describing the quest to bring Indian Buddhist scriptures to East Asia -- also quite relevant in every Buddhist society. Red Chamber is about a Qing dynasty Manchu boy's relationship with his female cousins -- rather more removed from Japanese cultural experience. (As well as the Western experience -- Journey to the West and Romance of the Three Kingdoms have had a greater success as cultural exports to Europe and the US than Red Chamber)