I would argue our predictions are correct but just not correct enough. For example in the mid-2000's everyone was predicting that with the "Internet of things" our refrigerator would be able to tell when our milk was low and order more. The internet of things is defiantly a thing but refrigerators aren't really a thing, it's more thermostats and lighting. Did that make the prediction wrong, in a way yes but also no.

So these countries can expect negative population growth for the next 30ish years (of native peoples).

You really gotta dry that tree out before Krampus comes to town!