Bitcoin will need to solve a couple technical issues before it really hits the mass adoption stage and I am a bit surprised Japan is pushing it so aggressively in it's current form.
I think scaling will be resolved soon, despite the fear mongering going. I hope Segwit gets adopted before UASF is needed, but even if UASF happens and creates a split chain we'll have one chain that will be able handle this kind of demand and once chain that can't... there's no reason for miners to be on the losing side. Bitcoin has been making slow and conservative gains relative to all other alts, once scaling uncertainty is over you can expect fireworks
RE: Bitcoin getting close to Mass Adoption in Japan?