Keep in mind whomever releases a Full Frame camera in any given period of time usually becomes "#1 total sales of full frame cameras". Sony took this title over the late spring/early summer by having the most in January - July. Canon held it the 2nd half of last year after passing Nikon.Canon needs to act quickly. Sony is now #1 in total sales of full frame cameras.........not just mirrorless but all full-frame. Canon is bleeding market share. Hard to believe that Sony has come so far, so fast.
Most of the buyers out there upgrade bodies around once every 2-3 years at best. A lot of people have been holding off on doing this as they wait for mirrorless which they knew was coming. Some of those people did bleed over to Sony. It'll be interesting to see what the charts look like in January. I would guess Canon will be back on top but wouldn't be surprised if Nikon is not in 3rd again. I suspect that in another 5 years Nikon will be looking much more like Minolta did just before Sony took over, especially with Panasonic making a strong push into Full Frame. I wouldn't be surprised if they are bought out as their engineers, talent and patents are very valuable.