Seems the PSP and eventually PS Vita both suffered the same fate as Sega's Dreamcast - cut down too soon due to piracy. At least that is what the publishers want everyone to believe.
I think it is their forcing fans to use their proprietary memory sticks that were uber expensive for less storage than SD options of the time. I am not saying piracy didn't play a major role, just that Sony forced gamers hands with that storage option.