My guess is this may increase but not by a tremendous amount. As Laika said, the Japanese system is very big and holds a lot of meaning for Japanese people beyond just playing baseball.
Plus, it's the kind of thing that may, down the road, strain the relationship between MLB and the Japanese league if more and more kids decide they want to come over to the US before they play in the Japanese league, skipping the while posting system, which is a pretty big money haul for those teams when they do have players leave.
I know this kid if coming to play college ball, not be signed as an international FA by an MLB team, so one might think there'd be no reason for the Japanese pro to care with respect to their MLB relationship, but it's all related.