I don't agree that the memory cards price killed the vita, you always had the option to buy the smaller ones and very soon after launch 8GB memory cards were bundled to almost every vita. The exhorbitant price of memory doesn't seem to be a problem with apple products like iphone or ipad atleast.
A large part of the handheld market got eaten up by smartphones and when your main competitor Mario, Pokemon, Zelda, Monster Hunter etc. plays there is little you can do.
Sony tried to give the Vita a massive push with aclaimed western franchises like Assasins Creed and Call of Duty, but in the end the effort was sadly not worth it.
Imo the Vita was ahead of it's time, playing PS2-PS3 graphics on the go was fantastic.
I still use mine, even ordered a new one from hong kong, to play some RPG