Like others have said, NX was described as "dedicated game platform".
It's different from the infrastructure Nintendo is preparing.
Also, it no longer makes sense to announce a console one year and release it the next. Specially in Nintendo's case.
We all saw how announcing and releasing both the XB1 and PS4 helped maintain the hype for those consoles.
The next Nintendo really needs that.
Not to mention that with Wii U sales so low, if they decide to announce it in 2016 and release it in 2017 the console simply won't survive that long.
Announcing it and releasing it in 2016 is the best choice - probably the only real choice - for Nintedo if it wants to keep whatever momentum it has next year. Because, from this point onward, Wii U just won't get the support it has had up to now.
