Like almost everyone alreadys said, Miitomo isn't expected to generate money, it has different purposes. OP seems to think it should be like every other mobile app. Basically, what you re saying is: Miitomo is too different, it will fail, Nintendo should have made Farmville instead. I guess EA would go that route, but this is Nintendo we are talking about.
Also, even if Miitomo never broke even, it would still be successful for Nintendo in generating brand recognition and broaden their user base. It is not a business model itself, but instead a part of a bigger business model. While a component of that might not be profitable, the whole will be. And finally, I think Miitomo couldn't have very large development costs and probably broke even already.
