Initially, I grumpily agreed with Sony's take on why big games don't work financially on the Vita. It sounded reasonable, but rather than accept the situation and attempt to deal with it, Sony seems to be casting the Vita aside, sounding almost embarrassed about its existence (see the Vita Buyer's pledge). Where's the drive to turn things around, as with the indies and old JRPG efforts?
It doesn't take much thinking to see several sources for potential Vita games, which while not massive, will prop up the mid-tier and encourage sales, attract further development etc, etc.
With the arrival the Unity Engine update allowing port-to-Vita options (although I'm sure its not quite that simple), there's a whole world of games that will work on the Vita. Older big-name titles that used Unreal Engine 3 should also run on the Vita through that dev kit (guessing its a stretch to downgrade a UE4 product). Sure, some fine-tuning, asset-stripping and power management is required, but that's not AAA development work.
More suited to the Vita, we have Sony and other developers already using several high-quality game engines (Killzone, Uncharted, Ubisoft's Assassin's Creed [less so] and EA's Need for Speed) - a lot of the leg work in development work has been done. Why not license out or open source the engines and let others (mod teams, indies, other allied devs) create the next wave of Vita games.
Its not like these engines are generating revenue sat on a shelf. Whatever route, if the Vita isn't going to get big-name games then fine, but as Sony has found through indies, if you open up the taps on other sources, especially in the global market, with a little encouragement, then games can still come flooding.