How much hardware does Nintendo need to sell per generation to remain relevant?

[zorg1000]

Soundwave said:

They are doing OK right now in terms of net income because the yen is weak, but if the yen were to go the other way, they would very quickly go back to earning a loss with their current sales/operating profit.

So you don't want to allow your sales revenue and operating profit dip so low that its at the mercy of currency fluctuations.

It isn't quite as simple as saying "well they just need to profit" ... making a profit is not always so straight forward. 

That's what I mean in the op, the number of hardware/software sold isn't necessarily the problem, it's that they have been selling hardware at a loss for over 3 years now, if 3DS & Wii U were sold at a loss at any point in their lives than their profits would be pretty good.