High cost + outrageous memory card prices.

Pointless 3g

3ds's already huge install base and library.

Really ? ... 

The launch was fantastic but the support overall is terrible. A launch doesn't define a platform's library. 

"Vita owners continue to buy more games per system than what is done on any other system" 

Oh please, don't make me laugh when it has one of the WORST tie ratio's ever a system could have ... 

Extra Credits put it best.

https://www.youtube.com/watch?v=REaUzHef9h4

Colin Moriarty jinxed it with his infamous article

my opinion on why the Vita failed is basically the same as Extra Credits

https://www.youtube.com/watch?v=REaUzHef9h4

but also has been said in this thread already the expensive memory cards and lack of marketing and the declining sales of Handhelds in general also played a big role into its failure

Regarding the last statement, this just tells us that you are uninformed on the subject. While VGC's consistently troubled tracking of physical sales tells one imperfect story, it completely neglects the digital side, and digital sales make up a higher percentage of Vita sales than they do on any other console/handheld. Devs have spoken out about the high attach ratio, indicating that it was over ten games per system owners many months back. That's actually pretty incredible. It makes sense, though. The Vita has an extremely core demographic, meaning that people who don't consume a lot of games aren't likely to buy a Vita. Meanwhile, the Vitas has more than a strong enough library to keep that core buying.

Regarding the first thing, you're making a fallacy. A launch doesn't define a platform's library (though the titles I mentioned go way, way beyond launch), but it does indicate early success. What we learnt from the Vita is that excellent games from new IPs and popular old IPs alike were not driving sales. The games were not the problem (though certainly we can endlessly posit that more games at least constantly help to some degree), because the system was not selling particularly well even when it was releasing quality, high-profile games much more than the 3DS was. Blaming a fancied lack of games is to not understand that the system and its positioning are the real problems. The Vita gets less high-profile exclusives now than it used to get because the system itself did not sell well enough when it already had the games. This is a bit of a chicken-and-egg scenario, and you're getting it wrong.

VGC double-posted for soem reason. I'd delete this if I could. lol

They buried the handheld while it was still alive. That is what went wrong.

LOL, dude said autopsy xD

It's a fitting word. It's dead, and we want to know what killed it.