The interesting part here is "what will japanese 3rd party do?" Smaller Traditionally ps4/vita/PC devs like idea factory will probably jump en masse to switch, maybe in a couple years will not even bother with a ps4 version. And bigger devs would be stupid not to at least make games for it. In fact I could see the next dragon quest going switch EXCLUSIVE because all that really matters for DQ is japanese sales.
And the big thing is if sony starts losing japanese 3rd party exclusivity, its going to be sandwhiched between the xbone S with its 4k blu ray and shared 3rd party, and the switch with ninty titles and all that japanese support even if a lot of it is shared.