3DS may be older, but it has an installed base that is generating profit.
3DS needs a replacement, because nintendo needs at least one successful platform. They are forecasting another decline to 7m (from 9m) - they know the 3DS is on it's way out.
The 3DS may be profitable, but it has also been stagnating for quite some time and is a pretty unhealthy platform when compared to previous Nintendo handhelds. Hardware sales are in a constant decline, its attach rate is the lowest of any moderately successful Nintendo platform to date, third-party support is sub-par and there's very little to look forward to on the first-party front as well. I feel this is mainly due to the fact that the 3DS went through most of its design phase well before smart devices redefined portable gaming, and was never really a product that met the needs of the current market as a result. A real answer to the smartphone boom (aside from the DeNA partnership) is much more crucial for Nintendo's dedicated gaming business than a hasty Wii U replacement.
Agree