if sony was about to drop the vita they'd never have released vita tv.
Most people don't realise that a main part of the plan for Sony is to get people into ps+.As ps+ offers you a lot some ps3/4 owners will tend to buy a vita(as they get 2 vita games a month for free) .
A win-win-win situation as gamers benefit,sony and publishers are also participating as the get money for their ps+ games.
And sony can try to combine vita with smartphone-sliders with analog sliders or these huge nvidia-touch-things(the small experia touchpads were too shity & too small)