it won't be that rare every retailer has it and hell even meijers has it marked to $19.99 and they still have it in stock
In stock now, I'm talking in 2 or 3 years.
My understanding is it sold horribly, so it's a game that might never be repressed or part of any "Nintendo selects" line. Think of something like Metroid Prime Trilogy, or Xenoblade. Sometimes you don't know it's rare, until after it's OOP and all of a sudden people start looking for it. (I lucked out in having a 2nd sealed copy of Metroid Prime Trilogy when it peaked out... and I believe I actually got that from Toys-R-Us for $19.99).
Of course I realize just because it is niche and on a Nintendo platform doesn't mean it would be worth a 2nd or 3rd copy. It could be more Madworld (coincidentally another Platinum games title) than Xenoblade.
I guess I'll just hang onto the one copy. I bought that assuming I'm going to get a Wii-U eventually. No sense in buying 2 or 3 copies when I don't even have the system itself yet.