In my honest opinion, i believe we can count Valkyria Chronicles as the Fable or Zelda for PlayStations now, the fanbase is Japan is a big one, Sega must realize this now between the first game, the re-launch of the first game, and the anime and so on and so forth.
Im willing to bet from here on out VC stays on Playstation stuff hence-forth.
and yes, those sales are rather unreal, even more so for a PSP game. aslong as japan keeps on lovin PSP it should stay alive for that reason alone, however localizations wont be to kind for us in the NA or EU...