Lack of interest in the EOP market and also unwillingness to compete with technology and marketing. The money people spend on non-pvp mobile game in the west is pretty dry. Massive pvp games dominate the market. Many titles are from companies owned by China and China has so much marketing power, workers, advertising and influence in the west. China's existing influence with pc and mobile games helps pave way for their pve mobile games in the west. China basically owns shares in so many game companies and has so many resources. JP companies wouldn't even try to compete with that because it's a waste of resources.
Also, many games don't wanna GL and newer JP games aren't necessarily beating out older ones so can't really gain traction.
What games are you look forward to, anon?