PSP had proprietary memory cards too. They were literally just trying to make a PSP2 with the vita.

The memory card issue did suck but as someone who only had a 16GB card it was blown way out of proportion. I never needed to have every game ever installed on my device at once. Would’ve been nice, but it never got in the way not being able to do so.

Nowadays you can get an SD to Gamecard adapter and with some homebrew installed use that for storage which is pretty cool. You can also replace the 3G card with an adapter too, but less people do that since it requires opening up the vita.