Well they can do alot, probably putting it out there with advertisements. Last ad I saw for the PSVita was the Call of Duty Black Ops Commercial.
Good games can be made for the Vita and they can look good too! For example look at Need For Speed: Most Wanted, it might not be a good game, but it for sure is a good looking one, out of alot of the games I’ve seen on the VITA this one jumps out to me the most, showing that EA can probably port alot of their games onto the VITA, Battlefield 3 for example.
As of now the VITA library is just filled with games which are clones of each other and Japanese games, and that doesn’t really appeal to the Western masses, they want more Call Of Duty, AAA titles, things like that.
Sony justs doesn’t want to spend more money on the VITA, I’m sure if they do they’ll have a system as popular as the PSP, its a powerful handheld. It just doesn’t seem like they want to do anything with it.