They'll restock all the rare stuff post-holidays, you can be sure of that. The cards thing is more a "we're thinking about alternatives" thing, so like 3 or 4 years from now people can still buy Smash Bros character Amiibo Cards to use with Smash Bros even if they never work with other games or have second printings.
Right now the demand is just outpacing the supply. They'll both even out once we're past wave 3 I bet.
The reason why there is this much demand is because they are seen as being rare/collectibles.
Nintendo is going to mess up that perception by going back to restock past figures when they still have the other Smash characters to release in planned waves? I think this is going to last throughout their Amiibo releases.