mirrorless doesnt have the lens support, and that's what takes so long to build up. I also dont think mirrorless kills DSLR's either. With low light, EVF's slow down a bit, and just not as accurate as ovf.
Try timing action with mirrorless, it just seems to miss (shot karate, and while I can nail focus, very hard to time shots with the EVF). A serious amateur may take a DSLR because it's established and proven.
Heck, I'm toning down my DSLR kit big time, but at the same time, I want to have a few zooms, where the DSLR will remain king for many years IMO.