Sure, as a customer getting into Sony handhelds for the first time I'd say that argument is justifiable.
As a customer who owns a ps3 and knows they went 6B into the hole padding it with features, I'd say it's not a big deal that I have to spend 30-50 dollars on a proprietary memory card.
Shit, mem cards on ps2 and ps1 used to be 35$ or so as well, and those were proprietary. I just don't see it as a big deal. Other people can feel free to do so.









