Portable games aren't on the same PR cycle as console games. A console game, they'll show you it six-nine-twelve months ahead of time, sometimes even longer (though I don't think anybody feels good about having to do a second E3 showing.) Portable games, they don't do the same level of advanced PR/pre-ordering. Partly that is because the games are generally given less development time. Partly that is because they're less high-profile titles both to the press/PR and to the fanbase. (Even though these were huge hits, how many Pokemon X/Y or Zelda ALBT videos did you watch before buying? And in that same times, how many WatchDogs or GTA5 videos did you watch?) And partly, that's due to old habits where portable games don't drive pre-orders in the same quantities and so stores don't book these games that far in advance.
Couple this with Nintendo's weird new PR strategy where they pull titles out of their Nintendo Direct magic hat and expect them to sell no matter when they're first announced, and you have a very slim line-up every single year for every single portable platform, yet a system like 3DS will still have people at the end of the year going, "Huh? I'm surprised how good a year 3DS had!"
...Vita's slim retail line-up sadly will probably not generate the same responses.