Well don't forget that Sony is putting out their own new device this year, the PS4K. That's far more risky than what Nintendo's doing.
HOWEVER, it also is likely to help Nintendo. It's not just a "what is Nintendo doing?" situation anymore with Nintendo releasing hardware when nobody else is, Sony is and Microsoft is rumoured to. As such, having it be an entirely new device rather than just a more powerful version of what's out there could be very beneficial, especially as what Sony is doing is risky as it potentially fragments their current pushing 40m userbase with future games. It's not the best way to create consumer confidence. That's why we don't have many N3DS games. As such, Nintendo having NX at this point could be quite beneficial