Things are not as black and white as some would suggest. The Vita came out with launch library of more games than I can remember for any other system. That doesn't include PSP compatible games, and does include at least one original AAA title in Uncharted. The unit deserves credit for that.
However, people rightfully expect a show like E3 to reveal the future support of any machine they own, and one of Sony's execs recently admitted
that they did a poor job of that for the Vita at the E3 conference.
Despite having 25 Vita games at the show itself, they only highlighted a few at the conference. The idea this year was to have a much shorter show, and they still wanted to cram a lot of content in so stuff got cut.
So the Vita is still a major part of Sony's plans; it has quite a few games out already for such a short time on the market, and there are dozens of announced tand unannounced itles in the works. They can certainly can do a lot more to support/promote it, and we'll see how well they do that in the future.
All I know is, if/when Tekken Tag Tournament 2 is announced for the system I'll finally get one.