Nothing did it in. PSP wasn't discontinued until 9 years after release and 2 years after its successor the Vita released. It just got old. There was a ton of games for it too. PSP had it's own exclusive versions of God of War, GTA, Kingdom Hearts, Killzone, Wipeout and Metal Gear, Final Fantasy Spinoffs like Crisis Core and Dissidia, cool remakes like Mega Man Powered Up, Maverick Hunter X, Castlevania Dracula X Chronicles and Ultimate Ghosts and Goblins. Of course can't forget the series that moved a ton of those PSP units, Monster Hunter.
I don't see how anyone can say that the PSP didn't have any great software. That system got a ton of support. The Vita is the one that struggled to get any support outside of Japan and zero from Sony