This set of handhelds came after mobile platforms tools had started being developed and refined by the 2009 when they would be receiving dev kits for either. Mobile has always been more profitable than their handheld ventures. Why go back?
The sad thing is Vita still compares favorably with mobiles and uses similar and in most cases indistinguishable IDE as most mobile projects. Sony simply hasn't convinced publishers to basically recompile for their platform as well. I bet their certification stuff might be more of a hindrance to boot. Theoretically there is next to no work at all in bringing most of the games found here over to the platform unless they use too much ram: http://en.wikipedia.org/wiki/List_of_Unity_Engine_games (This list is by no means complete just most prominent really)
I don't know how Sony failed to co opt mobile development with the Vita. Were I Sony I would be drastic and offer free Unity addons like ID@Xbox and lower licensing fees for handheld exclusivity and making a far more lax certification process.
micromanaging developers with certification requirements, like the need to include that ever-present "do not to turn off their console when a game is saving" message is silly. They should include it automagically as an api for Unity and Phyre Engine and their PSMobile suite. They do it all the time why make indies reinvent the wheel each time?







