Even though they only call this a "temporary" halt in production, and it in no way means that the last game cube has been made, it still isnt very good news.
What this says is that Nintendo is severly overstocked in hardware, hardware it isnt having very much luck in moving.
Why did they make so many cubes?
They must have thought they were going to sell them, this tells us that sales have indeed failed to meet expectations, and that management has come to the conclusion that they "MAY" not sell the inventory they already have, thus the temporary suspension.
Hopefully the last gamecube hasnt been made as this would indeed be another black eye on an already battered body, but only time will tell.