PSP wasn’t exactly dead when some of those other titles you listed came out. Software sales start to decline towards the end of a platform’s life and you started to see that with a couple of those titles.
http://www.siliconera.com/2014/04/24/natsume-still-supporting-psp-games-like-end-serenity/
All you have to do if busy is read the title and take a glance at the date it was posted. Now sure this game looks mediocre and Final Fantasy TYPE-0 is a more complex game but Square Enix is the makers of one of best selling RPG's and one of the best seller franchises in general, which is Final Fantasy. I know Nastume because I buy and play Harvest Moon. Natsume is no where near Square in money, fame or popularity. Yet low PSP sales or pirating didn't stop them from localizing a game to their fans (They didn't develop this game though)...