I think that Nikon is starting to sweat.
It is perhaps not surprising that of the big two, Nikon blinked first. After all, they are significantly smaller than Canon — less than a fifth the size. But blinked they have, and change is coming in the form of two very nondescript horsemen: the D5300 and the D610. The D5100 was available for two years before being replaced by the D5200. That camera has now been available for less than six months and we have its replacement. It's a very small update, but is being advertised by Nikon as a full update, and really, that's the important part.
This again brings me back to my post about the D610 and EOD 6D selling at discount. Was that the first sign of trouble, when they had to sell their much-ballyhooed cheapest full-frames ever at an even lower price to gain traction? Had they simply assumed that a lower price would make people come running, and that didn't happen?
Regardless, the point of greatest significance in this is that Nikon has released updates to major cameras very quickly. They've never done this before in the digital age. They are trying to appear that they are iterating quickly to keep the market interested and excited about Nikon products, years after people stopped being excited about Nikon products. So, yes, they're late to this realization, but they have at least realized it. Canon hasn't even had the good grace to do that.