They’re certainly going away — for a couple of reasons. First, it’s cheaper to manufacture something electronic than something precision-mechanical. Second, there are now sensors with PDAFs, so DSLR’s low-light AF advantage is going away…eventually, as those PDAFs improve. The stockpile of consumer glass gives manufacturers an advantage — if there’s a cross-mount adapter. Going from mirrored to mirrorless means the mount-to-sensor distance is shorter, making optical ‘room’ for an adapter without correcting optics, so that’s pretty do-able — without optical penalty.

I’m in no hurry. My D750s are pretty much the perfect camera for me.

Also: mirrorless cameras pretty much all have mechanical shutters (either in-lens like Hass, or focal plane). So ML does not mean all-electronic.