My friend has had her Panda pochette for about a year or more, and its SERIOUSLY started to rub off. She keeps it inside her Manhattan and uses it to hold her wallet/change, so she does use it everday. I was surprised how badly the panda had rubbed off, but I guess its because she treats it pretty harshly.
No, it's because the process of putting the design on is really intricate. The MC line is currently the one line that uses this process the most, so it would be hard to have so many at once that utilize the same process. Plus, Murakami was commissioned to create limited lines so that's also part of it.
I haven't had any problem with my panda...but I don't use it alot. I was at the store awhile back and my SA mentioned using a pochette inside larger bags./..I told her I only had LE pochettes and she emphatically said "do NOT use those inside your bag!"