I think the higher quality DSLRs and mirrorless gear will stick around for a while, but their market share will continue to decrease until they occupy a very small, very expensive niche rather like large format cameras do today.
In the meantime, software will continue to reduce the gap in photo quality between large sensor cameras and smartphones/compacts, until the difference in quality doesn't justify the expense of a 'real' camera for more and more people. The drift away from prints and toward small screens (i.e. phones and tablets) to view photos will also contribute, making IQ less important.
Even photo enthusiasts will be hard pressed to justify spending thousands of dollars when their buddies can get 90% of the way there with a camera costing a few hundred dollars (or essentially free, if it came with your phone), and without any training or effort to learn. Software will replicate the shallow DOF and bokeh effects, reduce noise in high ISO shots, remove camera shake in post, apply superb processing, offer amazing special effects that Photoshop would struggle to achieve - even tell the 'photographer' how to compose the shot.
I love photography now because I get a real feeling of accomplishment when I look at my photos in comparison with those made by non-photogs. When my shots made with a $5000 combo are largely indistinguishable from Joe Blow's, made with his smartphone, I will lose interest.
At 62yo however, with increasingly debilitating arthritis, I may have to give up DSLRs well before then anyhow.
5D3, 7D2, EF 16-35 f/2.8L, EF 24-70 f/2.8L II, EF 24-105 f/4L, EF 70-200 f/2.8L II, EF 100-400 f/4.5-5.6L II, EF 1.4x III, Sigma 150mm macro, Lumix LX100 plus a cupboard full of bags, tripods, flashes & stuff.