DSLR or SLR was a confusing title any which way. SLR = single lens reflex. The "single lens" referred to the fact that there was no separate view finder lens (like in a Rollei twin lens reflex box camera). Mirrorless is still single lens, without the "clunk click every trip" of the (mechanical) instant return mirror. I have spoken to photographers who thought "single lens" referred to the kit zoom that came with their DSLR! It does and it doesn't! At one point, to get away from the clunk click every trip, Sony introduced their Alpha series cameras, which incorporated a "see through" mirror which did not have to get out of the way to take a pic before returning. Not exactly mirrorless, but did get rid of the clunk click. I believe that Sony Alpha users sometimes had ghosting problems.
"Reflex" refers to the prism that bends the light up to the viewfinder, which, with an electronic viewfinder is unnecessary.
There will not always be DSLR AND mirrorless - are there any photgraphers who seriously believe that mirrorless will not win the day?

Ditto. Me thinks the lack of an EVF is the reason for the dismal sales of the K-10 and the Q, as well. (It was also not a very aesthetically pleasing camera, IMHO). In the case of the K-01, the EVF technology available then was nowhere near what it is today, so I guess I'll give Pentax a pass; however, with the current and later Q models, there was really no excuse for not having an EVF (even an optional hot-shoe version if including one would price it out of marketing feasibility). Of course, some would argue there was never a feasible market for the Q anyway, but that's another argument for another day.

DSLR or SLR was a confusing title any which way. SLR = single lens reflex. The "single lens" referred to the fact that there was no separate view finder lens (like in a Rollei twin lens reflex box camera). Mirrorless is still single lens, without the "clunk click every trip" of the (mechanical) instant return mirror. I have spoken to photographers who thought "single lens" referred to the kit zoom that came with their DSLR! It does and it doesn't! At one point, to get away from the clunk click every trip, Sony introduced their Alpha series cameras, which incorporated a "see through" mirror which did not have to get out of the way to take a pic before returning. Not exactly mirrorless, but did get rid of the clunk click. I believe that Sony Alpha users sometimes had ghosting problems.
"Reflex" refers to the prism that bends the light up to the viewfinder, which, with an electronic viewfinder is unnecessary.
There will not always be DSLR AND mirrorless - are there any photgraphers who seriously believe that mirrorless will not win the day?

The one place I might not agree with your answer is your emphasis on the mirror "click-clack". Experiment with your DSLR; shoot some pictures "normally" and some in "live view" / "mirror up". With my Pentax K-mount camera, the shutter makes as much noise as the mirror does. That may be why Sony is experimenting with the "electronic shutter" that has caused so much discussion, to get away from shutter noise also. Personally I like the solution Pentax chose for their Q-mount MILC line; each Q-mount lens has a whisper-quiet leaf shutter embedded in it, so that is the camera I use when someone asks me to take pictures at some ceremony, where noise matters.

Many Canon and Nikon users have been anxiously awaiting their respective companies to offer a truly professional mirrorless solution. With the Sony a9 taking aim at the top DSLRs, that clamor has only increased in intensity. A Nikon spokesperson has recently confirmed that the company is developing a mirrorless camera that "should compete in the mid-range and high-end DSLR [market]."

In speaking to DPReview, a Nikon spokesperson confirmed that the company is indeed developing mirrorless products that "offer the performance prospective customers expect, including the ultimate optics performance, image-processing technologies, strength and durability, and operation." The spokesperson declined to elaborate on details, and it's unclear how such a camera would integrate with the current product line, in particular if it would introduce a new lens mount. Nonetheless, the spokesperson indicated that the camera would aim to compete with professional DSLRs. While details are very scant at the moment, receiving official confirmation from Nikon is a great sign for those who have been long awaiting the company to step up to challenge Sony and Fujifilm. If both Nikon and Canon step into the mirrorless market with full force, it could cause a major paradigm shift in terms of the DSLR/mirrorless landscape and will no doubt propel development forward all the more quickly.