yeah, some people not knowing or not listening to a band, it means nothing... ask me anything about contemporary hungarian music and I will look at you like an idiot. I have no idea who the current superstars of my country are
It just depends on the person you meet. People's taste also changes over time. I don't think those bar guys don't know who X Japan are. They just don't listen to them, which is perfectly normal... I also don't listen to Omega or P.Mobil, the once-great rock bands of my country, but I would instantly recognise any song that plays on the radio, cuz they are part of the history of music here and everyone knows them. If a camera crew would ask me who my fave bands were, I wouldn't say Omega. But were they to give another concert, i'd probably be there.
It is probably the same thing with X Japan back in Japan. They are the Golden Kings, the old days' guy, respected and loved, but they are 50 year olds, you cannot expect 20 somethings to name them as their all time fave. It certainly is different for international fans who started to discover them out of the blue, like me. it's different musical demographics and dynamics. That's all.