Sony had no plan for bringing big games out consistently. They just expected the games to come.

Selling less than 7.5 million of the 50 million sales and less than 15% market share. I do not see the PSVita staying above 10% market share this generation as the 3DS continues to surge towards 200 million sales.

2 Major issues the Vita has as of now.
- Priced to high. For whats in the device, yes it's worth $250 as a dedicated handheld, but in this market, most portable gamers are not willing to pay that much for a handheld. $150 is the sweet spot for handhelds.
If Sony can get the Vita down to about $150, sales will rise. And with the PS4 selling well, that will only help spur Vita sales.
- Memory cards are priced to high. The cost of a 32 Gig SD card is around $20 at Radio Shack, Sony needs to correct this ASAP. Sell the 65 GIG memory cards at a more reasonable price and gamer's will purchase more games....... Keep on Gaming.

Lack of advertising
Lack of noteworthy exclusives
High memory card prices
Shrinking handheld market

It's all because of Sony, besides a few games, almost everything is a port, and even from the PS3! It's all Sony's fault, the price, the memory cards, and the support it doesn't get...

Ultimately it was the games. The PSP did fine despite it's price, but it had a great line up of exclusives backing it. The Vita on the other hand has relatively few, with it's highest rated game being a PS2 port :/ The loss of monster hunter also played a lot into it. That was pretty much the PSP's counter to Pokemon in Japan.

It's a shame really. The Vita is an amazing piece of hardware.

This too; Sony are used to relying on third party support which in this case didn't show up, at least not to the degree that was needed.

lack of marketing. lack of big names. propietary memory cards

I don't know. It's unfortunate such a great device will probably be remembered as a flop.

The Vita currently only has 20 exclusives. That's it's. Literally has no games that make the system unique and worth a purchase.  Atleast in the west.  In Japan it has a bunch more exclusives.