Headline says it all. What happened to all of the vita memory cards? Every major store seems to be sold out/no longer stocked. Are they no longer being produced?
Mod Edit: Edited labels. Look her for more information!
I noticed they are not as common in-store, as well. This started last year, right after I bought mine. Sony then had the official price drops on memory cards and introduced the 64GB card. I still see them on shelves, but it's usually just 1 size (the 16GB or 32GB) and not a very large selection.
You should have no problem finding them online. I can only assume Sony is planning new packaging, larger sizes, or... I don't know, another price drop? Maybe what is available right now is all there is, and that is why it seems like retailers are just dumping their current stock. We'll see at E3 if Sony addresses the future of the PSV. Until then, anyone's guess is as good as mine.