Bit of a cheap way out, that. Most games don't use touch controls (at least in my experience). Also, there are (once again me talking about fragmentation, what a surprise), games that work in physical form but not digital (and vice versa), and games that work in some regions and not in others.
That said, I love my PSP, and I love my Vita. I play PSOne classics on my PSP anyway, so I'm fine. Ditto with PSP games.
A lot of games you can't even do anything without using touch controls. Some games have no controls for menus, you HAVE to use touch. Murasaki Baby is one that is ONLY touch compatible and I guess they COULD rig up the controls to work on the Vita T.V. I just don't know if it'd be worth it.
Vita games being uncompatible makes sense, due to the front and rear touch. However PSP & PSone has zero technical reasons not to work.
You really can't blame Sony for this. I know everyone will anyway, but publishers and some developers are why it won't work. They have to get the O.K. and do the testing to make sure it works and is playable on the Vita TV and patch what ever isn't working properly.
Disgaea 3 for instance has back touch controls, and in Japan they patched it, but I don't think it's been patched in the U.S. The controls are kinda negligible, but Sony can't know EVERY feature of EVERY game and whether it's not playable.
There's also 1 developer I heard that pulled all their games off Vita T.V. support because "We consider it a completely new device" and they're probably going to try and make a new Vita game to get you to pay full price for.
Things are fragmented, and that sucks, but on the flip side most new games should support the Vita T.V. and you can always get a Vita later. The only way they could have prevented this is by making the Vita TV like 3 years ago.
Sony can't demand that companies suppor the Vita T.V. because then that hurts companies like Drinkbox and their game Sever where the game is designed around specific touch controls and being accurate.
There's just no easy answers. You either stomp on indie creativity by demanding everyone support the PS T.V., or you hurt indies or have no recourse for laid off devs or companies bought sold or have gone out of business and therefor don't have the resources to patch support, you have the risk of releasing a game that doesn't work fully because of some unexpected reason that it won't work on the Vita TV.
I'm just glad sony made it so I can just buy a vita copy rather than deciding between a PS3 and a Vita game for non cross-buy games.