The 3DS does not have the screen specs to do streaming of Wii U games. It can't do all the things the new controller can. Nintendo chose to keep costs down on both fronts, which is something Sony doesn't do.
Of course, we don't even know if the Wii U will make use of multiple Wii U controllers.
With Vita, there's probably a good chance you already own a PS3, so the major cost of a new home console is cut. The Vita doubles as a standalone portable, so if you want to own one console and one handheld, there's no extra cost in buying another controller. Sony could push this aspect if they choose.
Granted, these might be different markets, but if the style of gaming does pick up, then it would be reasonable to expect a screen-only controller from Sony, but they'll already be able to match features and get games out using Vita.
What the companies really want is for everybody to own a handheld to bring to friends' places. Of course, this didn't work so well with GBA/GC, and probably only phones/tablets have the penetration to have that happen successfully.
I expect Microsoft to try to integrate play between Windows Phone and their console at some point, and now that Sony is in full control of their phone division, they could go in that direction too.
Actually, EA is already doing this with their games on tablets and phones.