Nintendo reiterates that some amiibo are unlikely to be restocked after selling through initial shipment due to limited shelf space

[fleischr]

The truth is that if Nintendo has retailers that want to stock all the different Amiibo characters, then by all means they will meet demand. Maybe not the same model, but you'll have many characters continuously available (e.g. you may see variations over time for collectability)

Amiibo fulfills a major goal Nintendo likely has: build popularity of 2nd and 3rd tier mascots