Because China is no longer in play. Haven't you heard that the Chinese exchanges were shut down because they were banned from trading for fiat? As a result some traders moved to Hong Kong and some are probably using Japanese and Korean exchanges, because since that happened the volume in Japan went up by a lot.
BTC is not going down, it's trading between resistances 7-11k with 6 being the bottom. It may take a year before we see another ATH.