I know some folks may think I am a knuckle dragger, but I am with Steve. I will keep my Nikon DSLRs until they or I die. I relish the feeling of seeing something I want to photograph and use the camera almost like an extension of my hand and eyes to get the photo. Likely it is a sign I am too set in my ways to learn a new system.
More often lately I encounter people using mirrorless systems. They seem satisfied with their gear.
So far though, I have not seen a mirrorless image that I could not get with my old DSLRs. And I have a lot invested in the bodies and lenses.
My primary cameras nowadays are the D850, with a grip, which gives me 9 frames per second, the D500 which gives me the same autofocus function as the D850, with 10 frames per second, and the D5 for low light situations.