They probably just made so little for each system because it's such a shitty Limited Edition therefore it looks like it has high demand and it's selling out fast when it's actually not. I'm fairly certain people aren't flooding the listing for a purse sized satchel and a flimsy poster. They could have taken this the normal LE route and made tons more sales, especially from people like me who tend to buy all their LE's (except this one obviously).
I personally think it's a neat package and the fact that they apparently only made a small amount makes it that much cooler IMHO. Frankly, I was starting to get tired of the standard NIS LEs that they have been pumping out for literally every game in the past few years.