The PSP was supposed to focus on "console-like" games, not ports of actual console games.
Sony has pulled no punches when it comes to flaunting the hardware superiority of its handhelds. Both the Vita and the PSP were marketed as more "console-like" than their competitors, and with the Vita's inclusion of a second analogue stick, that description is as apt as ever. However, developers may have taken the "console-like" description too literally, according to Sony's marketing VP for handhelds and consoles, John Koller.
"The issue that happened with PSP is we got overrun with ports," he told Gamasutra. "It became very difficult for us to define what made PSP unique. The content development became a bit unstructured or decentralized, in that we got a lot of content that was on PlayStation 2 and got thrown over to the handheld."
While the Vita has seen a number of ports thus far, presumably to bolster the handheld's anemic library, Sony is trying to guide publishers away from straight ports. Instead, Sony is pushing for more titles like Assassin's Creed III: Liberation, Call of Duty: Declassified and Uncharted: Golden Abyss big-hitter, console-like experiences that are only available on the handheld. System sellers, in other words. As brilliant as it may be, Gravity Rush just doesn't have the franchise clout to sell the hardware.
Much like the Cross Play and Cross Buy programs, which allow users to swap games between their PS3 and Vita, this seems like another attempt from Sony to stop the PS3 from cannibalizing the Vita's already flagging sales. Sony has sold 2.2 million of the handhelds to date, a far cry from the 3DS' 19 million. The PSP sold around 71 million units total.