According to the Wall Street Journal DSLR sales fell in fiscal 2013 by 10%. Pocket size point and shoot cameras by even more and DSLM (mirror-less) cameras by only about 3%.
All of this is in part due to smart phone cameras of course.
....there are multiple factors involved in the lack of sustainability in the DSLR market. Saturation is possibly the main culprit.
The OP plays the classic game of having a pre-conceived notion and then trying to make (partial and misleading) statistics "prove" the conclusion.
I would agree that saturation plays a much larger role in any decline in DSLR sales than either cell-phone or mirrorless cameras (including both fixed-lens and interchangeable lenses.)
Over the last decade, digital technology followed a classic pattern. It was a disruptive technology that made everything that went before it (film) obsolete. The worldwide conversion to digital drove DSLR sales more than anything else. And, because it was an immature technology, the pace of development and resultant obsolescence (either perceived or real) meant that buyers were replacing their cameras at a much more frequent pace than historical market trends. (A film SLR was good for a minimum of 10 years, often much longer).
Now, the initial pent-up demand for digital technology has been satisfied and the pace of development is slowing. It's a natural cycle and, while early adopters and gearheads will be disappointed, most consumers are likely to settle back into the pattern of replacing their DSLRs much less frequently – just as they did with SLRs.
I doubt if any of this comes as a surprise to Canon and Nikon – both long time leaders in the marketplace and no doubt well-positioned for the long haul. This is one reason why I personally would never consider any of their competitors for a primary system investment. (I would consider Fuji for a secondary system, but would not be buying into the system to the extent I have Canon or would do with Nikon).
Being more familiar with Canon than Nikon, I think I see the company developing and experimenting with strategies to retain its profitability despite a shrinking marketplace.
They have developed a mirrorless interchangeable lens system in the most established DSLR format -- APS-C;
They are offering a traditional DSLR in a size that is competitive with mirrorless;
They produce two top-selling full frame cameras racking up sales that far exceed their competitors;
They set an industry standard for high-end APS-C with their 7D and are likely to unveil the next generation soon, giving us a very good idea of where they see that market headed;
The are rapidly re-purposing their point-and-shoot models to focus on smaller, but more stable, niche markets;
They are using their market position and expertise to capture a growing segment of the video market up and down the line from entrance level to multimillion dollar Hollywood productions;
They are making major plays for other rapidly growing markets, such as security;
And, the list goes on and on.
The jury is still out on the future of mirrorless. Right now, it has been a bust in Europe and the Americas (not just Canon but all manufacturers). Some people believe that the relative success of mirrorless in Asia is a sign of the future. But, it's entirely possible that the opposite is true. Is the Asian market on the cutting edge and showing the way of the future? Or, will the initial fascination in Asia fade and consumers there fall into the same pattern as European and American enthusiasts -- ultimately deciding that the compromises required of mirrorless interchangeable lens cameras are too great and turn instead to DSLRs?
Interesting that on this forum, there is such an intense debate over what is really an insignificant point -- whether the future lies in optical or electronic viewfinders. Really, who cares? If electronic viewfinders reach a point where they offer more than optical viewfinders, the technology will transition. If they don't, then optical viewfinders are likely to remain the industry standard. Other than a fascination for technology that borders on being a fetish, there is no logical reason to care.