It's going to happen to a LOT of Wii U physical discs imo.
Soon as Nintendo announce they are stopping manufacturing Wii U units - you watch - the price of the made but not sold consoles will rocket and so will the residual value of all physical discs.
The whole Amiibo thing is a stark reminder that the world just loves collecting Nintendo.
Yes the world is insane for Nintendo collectibles.
Kinda wish I had collected a few and left them sealed.