No, Sony has not abandoned Japan. As many posters said this thread was premature.
PS4 sales have already improved a lot even though only spin-offs have been released like DQ Heroes, MGS GZ, Yakuza Ishin+Zero, FF Type-0 and RE Revelations 2 (VGC has yet to show Bloodborne boost).
I think it's reasonable to believe that sales will improve even more with releases of more quality PS4 exclusives that appeal to the common Japanese gamer. PS4 still doesn't have the Japanese mainline blockbusters like:
Final Fantasy XV
Resident Evil 7
Metal Gear Solid V: The Phantom Pain
Gran Turismo 7
Kingdom Hearts 3
Hot Shots Golf 7
Dragon's Dogma Online
Star Ocean 5, Persona 5, next Tales of game and all the other popular JRPGS
Dragon Quest XI (not in the slightest confirmed but would improve Japanese PS4 sales as well)
Monster Hunter 5 (not in the slightest confirmed but would improve Japanese PS4 sales as well)
etc.
