About that mirror ... First there was the blackout from the lifted mirror. That lasted about 50 years, until the instant return mirror appeared mid century.

About another 50 years later we have moved the focusing screen from the top of the camera body to the actual film gate, which eliminates the need for the mirror. Acoarst that also eliminated the need for any film as well, thus nicely avoiding any conflicting claims over the limited space in the film gate.

For historians, let’s note that full time liveview cameras have been in routine commercial use since 70 yrs ago. They just weren’t very portable, as clearly shown below:
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I keep trying to exit this seemingly exhausted thread, however you're giving me something else to write about.

Cars with manual transmissions are still available in the US, but very few people buy them these days, and the demand is dwindling. Yes, this is analogous to people still buying and using older camera technology. Old and new will still get you where you're going but in a different way. New technology in mirrorless cameras will eventually open up new doors, especially when the technology in advanced cameras like the Z9 trickle down into consumer oriented models, but right now, other than smaller size and quieter operation, it's mostly a wash between DSLR and mirrorless at the consumer level.

By the way, I've visited the UK and Ireland a number of times, and I rented a car on each trip. Cars over there are still dominated by ones with manual transmissions. I got frustrated with shifting with my left hand. It was a bit disorientating, and I'd find myself "downshifting" into 4th gear in roundabouts. Not a good thing. Anyway, after two trips, I started renting cars with an automatic transmission. In every case, even though I booked one type of car, I'd end up with something else because they would typically have a hundred cars on the car rental lot but only 2 with an automatic transmission, always more expensive than the car I booked. They had to honor my request, and twice I ended up with a Mercedes for the price of a compact car.

Consider the data presented by Ken Rockwell at https://www.kenrockwell.com/nikon/nikortek.htm

The 'D' lens is both a 'D' designation on the lens, and more importantly, the autofocus implementation that depends on the camera providing a mechanical coupling between camera and lens. There is a screwdriver thing that pokes out of the camera that couples with a slotted rotating coupling on the lens. This screwdrive coupling rotates to move the lens in and out for focusing. The mirrorless FTZ adapter does not feature this coupling, leaving all ancient AF capable F-mount lenses as manual-focus only lenses.

Consider the data presented by Ken Rockwell at https://www.kenrockwell.com/nikon/nikortek.htm

The 'D' lens is both a 'D' designation on the lens, and more importantly, the autofocus implementation that depends on the camera providing a mechanical coupling between camera and lens. There is a screwdriver thing that pokes out of the camera that couples with a slotted rotating coupling on the lens. This screwdrive coupling rotates to move the lens in and out for focusing. The mirrorless FTZ adapter does not feature this coupling, leaving all ancient AF capable F-mount lenses as manual-focus only lenses.