I've never heard these terms. You had either "western RPG" or "computer RPG" for technical/system-focused games like Ultima, Baldur's Gate, Diablo, Fallout, etc

I've never heard these terms. You had either "western RPG" or "computer RPG" for technical/system-focused games like Ultima, Baldur's Gate, Diablo, Fallout, etc or "Japanese RPG" for story-focused games like Final Fantasy, Dragon's Quest, Terranigma, Star Ocean, etc. RPG originally referred to the former, as they came first. JRPG was an offshoot of it, from Japanese developers influenced by the genre but putting their own spin on it. So there is no "take over"; just the offshoot fading.