Vita was a terrible name.
Sony has the best, most consistent, most easily understood naming conventions of all time. Only rivaled possibly by the "Super Nitendo."
Should have been called the PSP 2 from the start. The PSP was successful enough for them to build momentum with a sequel. "Vita" was nonsense - not on brand - and with such little marketing, like almost nobody knew it even existed. And if they saw it on the shelf, they had no idea what it was.
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Past that - memory card pricing wasn't the issue. It was the complete lack of internal storage, demanding a card on day one to save games. Had they thrown a gig or two in there, nobody would have had huge issues... and they'd have still made money on digital-only people. It probably was a nice margin for Sony.
Also, needed more flagship titles, instead it had B-tier spin-offs that tried to be console-like but were really just watered down versions of what was on PS3/early PS4. If it would have had a real COD (with crossplay?), a SOCOM, a Monster Hunter, and its own GTA (or heck, even a watered down GTAIV), it would have done much much better.
System had like... nothing coming out after the first 12-18 months.
(I bought one Day One. Liked it a lot. Had a lot of fun. But think it could have been so much more).