I found a link to this article written last year, before the K1 was announced. It gave me some insight into why Pentax made the gamble to go mirrorless.
Canon Hanging on to Mirrors Means Opportunity for Sony, Panasonic Cameras - Bloomberg
What caught my eye was the term paradigm shift, and I think they are on to something.
I love the SLR/DSLR viewfinder. I can't imagine using the K-1 to produce photos as easily as I do now. But I also know there is a old saying that goes, "People don't know what they like, but they like what they know." I'm willing to give new technologies a chance.
Allow me to make a few observations from my recent outings. I'd be interested to know if they match up with what any you have experienced.
Over the past couple of months, I've taken pictures of my nephew, his girlfriend, and their cheerleading team at basketball games. There were two people with DSLR's in the whole place. The student photographer, and me. There were a number parents/older adults with point and shoot cameras.
By far, the greatest number of pictures were taken with cellphones, by teenagers, and adults.
What really struck me was the reaction of young people to the two technologies. They did not notice pictures being taken by the mirrorless cellphone technology. They
did notice my DLSR, even though I was using my shortest lens, an A 50mm f1.4. They seemed much more self-conscious when I took pictures.
It is possible that may be my own fault; due to the way I approach photography. But I am conscious of that possibility, and try to minimize that.
I think the paradigm shift goes beyond mirror vs. mirrorless. Many students do not own computers, and have no desire to do so. I get the impression that most picture taking is done by cell phone, and uploaded to facebook albums. Almost all cellphones use mirrorless technology. Many can't imagine holding their eyes up to a viewfinder.
Getting on computer to do facebook happens at a friend's place, sometimes infrequently. I might be wrong, but I think the new design is partly a cute, "don't take me seriously while I'm taking your picture" message for a young generation, while still having some serious power built into a camera, power that will take some people to the next step of serious photography, the use of additional DSLR lenses.
We all know that the expense is not in the body of the camera. A company really makes it's money if it can sell quantities of lenses and accessories for those bodies. Like Iphones and apps.
Here's specifically where I think the paradigm goes beyond mirror vs. mirrorless. I think that all the major DLSR/point and shoot brands are in for major problems if they don't build in wireless communications. That will allow the current generation to access the facebook type technologies that are so in vogue today. A significant number of kids won't put up with the added step it takes to transfer images from a camera/card to computer and on to FB.
Rather than be a bold new step, mirrorless technology may be a fight for survival.
I did not search out any statistics to back up what I say, but my observation of a younger generation seems to speak loud and clear (at least to me).
Your observational mileage may (and probably will), vary! And that's okay.