I don't see the DSLR going anywhere anytime soon. The advent of mirrorless cameras does not constitute a life-ending event for DSLR's, or any other type of camera design. The advent of mirrorless simply expands the available pool of camera types, diversifying the options and making it easier for each individual photographer to get the camera gear that best suits their needs and style. Mirrorless cameras certainly have their advantages, but they also have their disadvantages. No single type of camera can ever service every need perfectly.
The DSLR was the best option in most cases until now, and while I'm sure many photographers will leave them behind in order to progress onto newer technology, many more are sure to stick with them. In particular, I think people who regularly shoot a lot of action will find the very small size of mirrorless cameras (which is supposedly one of their supreme appealing attributes) a bit too small for the job. I recently upgraded from a 450D to a 7D. Aside from the amazing advancements in AF and improvements to just about everything else, the SIZE is one of its most appealing factors. It fits my hands so much better than the 450D, and its a lot easier to grip. Combined with the larger size of a telephoto lens, holding, panning, and zooming are very easy. I can't begin to fathom how one would hold and manage a camera system half the 7D size for capturing lots of action (sports, wildlife, birds) without particularly petite hands and considerable dexterity.
Smaller size also means smaller lenses, and smaller lenses mean smaller physical apertures. Physical aperture size is a very important aspect when it comes to image quality, particularly the quality of background blur. Anyone who has ever tried to use a basic point & shoot camera for serious photographic work where DOF was a critical artistic factor will understand how smaller apertures can pose a serious problem. Granted, mirrorless designs lend themselves to lenses with larger apertures than the majority of point and shoot cameras, however they will be a limiting factor in many cases.
Optical viewfinders are something you can't mimic. Electronic viewfinders are handy as they allow the mirror to be eliminated, but they have specific limitations. For one, achieving high enough pixel density necessary for being viewed so closely is currently impossible, and extremely difficult even with the necessary technology to achieve it. Compromises have to be made on that front...either using a resolution lower than would be idea, resulting in visible pixels, or using pixels that can emit all three primary colors (RGB) and cycling between the three colors on each pixel at a very high refresh rate. Both compromises reduce the final quality of what you see in the viewfinder. They are simply an option, and photographers who's needs don't demand what an optical viewfinder offers are likely to be quite happy with electronic ones.
When it comes to frame rate, there are limits to whats good. The article mentions a 60fps frame rate. Could you imagine how much memory card space you would need to capture sequence after sequence of RAW images at 60fps?!? Its astounding how much disk space you can use with a mere 8-10fps and 18mp RAW images...the 500-600 photos per card that I'm used to literally disappears in a tiny fraction of the time it took when I was limited to 3fps. Thats nothing to mention of the fact that 60fps is more than twice the frame rate preferred for most cinematic-quality video and movies...24fps, and double that of standard television at 29fps. It may be intriguing that cameras with electronic shutters can capture images that fast, but from a practical standpoint, a lower frame rate is more useful.
In the end, the SIC article comes across as a little naive, given the facts. Film SLR's are still fairly widely used today. Medium format film cameras are still fairly dominant in that format. Large format view cameras, based on one of the oldest camera designs since the advent of the camera (and the probably 1st generation cameras), are a staple of many of the worlds best landscape and studio photographers, and the industry for brand new large format cameras is quite large and profitable. The DSLR will probably diminish, both in growth and total usage, over the coming decades, but it will never disappear. It will likely remain as a primary option for photographers alongside "3rd generation" cameras, and whatever rises up in the future as a "4th generation" camera (can anyone say Lytro?)