I do think iPad is killing Vita's potential. Look at the sales of both platforms since launch, why isn't Vita pulling such numbers? Probably because people buy other mobile devices, such as tablets. Sure iPads don't offer the same quality gaming experience than Vita, but they offer so much more than gaming. And this Retina screen: technophiles will all fall for it, it's that irresistible.
Kinda like the Kindle, 3DS is saved by its price point (and its mascots). More than ever, now new iPad launched, Vita also needs its price cut.