I'm not sure if "simple" is the right word, sensor stabilization is way, way simpler.
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Anyway. Yes. The DSLR is not going to be around forever. I've said it before and I'll say it again: eventually there will be a push for larger sensors and the DSLR platform is awkward for medium format.
Second, mirroless is less expensive and mechanically simpler. Fewer moving parts means warranty service is going to cost less. Inevitable improvements will eventually permit a fast electronic global (or at least functionally global) shutter, and cameras will at this point no longer be mechanical at all.
EVFs have improved significantly over the last few years. a 4k display with a frame rate of 120fps (if taking into account latency) will likely be indistinguishable from an optical viewfinder, and a 6K display most certainly would be. These kinds of numbers are certainly rational expectations considering that VR seems to be a technology that people are at least excited about.
EVFs likewise perform better in low light provided that latency can be corrected, and even without latency corrected, I'd rather have a laggy viewfinder that I can actually see than one I cannot see anything at all, while focus assist is *significantly* more useful than a rangefinder or microprism, imo.
Video can also be viewed naturally from the viewfinder without having to add silly eyecups.
I do not think DSLR is dead, but I think it will be in a few years, my guess is in 10 years professional cameras will not be mechanical, and within 5 years Nikon and Canon will be very much on board.
From my experience, my X-E1 I bought on a whim with all it's flaws is a far superior shooting experience than my Sony A700. The a700 is a solid camera, and really does have a very nice viewfinder, too. But overall, the Xe-1 is just "better".