3DS hardware sales will not keep Nintendo afloat alone, but as part of the overall picture it will do OK.
What I imagine will happen is that Nintendo will subsist on their cash reserves for a year to a year and a half before the 3DS starts to support Nintendo via software sales. The Wii U will continue to accrue software and hardware sales until it breaks even between two and three years from now, more or less as Nintendo EOL's it.
A year and a half of strong losses (and maybe a bit more) will be counterbalanced by four years of modest profits. Gen 8 will make for an overall profit for Nintendo, albeit a small one. Lean times for the big N, but not the end of the world.







