My gut tells me that Sony's JPN wins are driven by Switch supply issues or MHW spikes.
Yeah Japan is only due to MHW, everyone knows that. The region that really surprises me is NA. Nintendo winning NA consistently. Europe I expected Sony to be dominant in though
I think a lot of that has to do with age: most of us have had our PS4s for years now, and we just got or are getting our Switches.
Combined with the very accessible launch price and portability of the Switch, it's well-positioned to be the new NA leader.