All a head start means is that the X bone and PS4 will be old hats when the NX comes out.
Nintendo is going to be aiming for a larger market with the NX. Nintendo will also be also aiming to make the old repetetive and stagnating console market obsolete. It will not just disrupt the competition, but will strike to dismantle it.
Will Nintendo launch with some hit software to kick off the NX era? Let's say they will, and so Nintendo dominance in the market will return immediately. Microsoft and Sony are aiming at smaller targets, 100 million hardware units. Nintendo will likely be aiming for their numbers last generation, almost 260 million hardware units by the end of the next "cycle" if it will still be that.
I describe myself as a little dose of toxic masculinity.
