I understand where this "Nintendo must get into mobile" idea comes from. Folks look around on the subway and see that everyone is on their smart phones, and many are playing games. It's still very unclear to me however, to what extent smart phones are affecting Nintendo's business, and how Nintendo should adjust their business model in response.
Nintendo just announced[1] that Fire Emblem: Awakening for the 3DS smashed franchise sales records, selling 180k copies in the first month (a month plagued by shortages[2]) and selling more than a third of those units via their own digital distribution store. For perspective the lifetime sales of the previous Fire Emblem title was only 250k.
This game is selling out at $40 and 1/3 of the sales are online sales that they don't have to share with anyone else (still $40!). One of the main reasons why I don't think Nintendo should become a software only is company that I don't see how they can remain as profitable if they had to adjust their prices for the realities of the iOS market and had to share their profits with Apple. The most profitable games on mobile stores are free to play titles, and while I think Nintendo should experiment here and develop their own F2P games to test that market, I don't see why they couldn't do that on their own platform.
[1] http://venturebeat.com/2013/03/14/3dss-fire-emblem-awakening... [2]http://neogaf.com/forum/showthread.php?t=511036&highligh...