Well, there is a bit more to the story.
What you have seen from your older lenses might be good enough to please you now, you might be pleasantly surprised to see what more modern lens designs might do with the D850 if it were possible to adapt them to it (they can’t, unfortunately).
The camera and lens companies say that the shorter lens-to-sensor distance of mirrorless vs DSLR designs, plus the larger diameter lens barrels allowed by redesigned (bigger) lens mounts, makes lenses very much easier to design and optimize. That means better sharpness, less coma, and fewer aberrations for the same or less design effort and manufacturing cost. All good, right? Throw in VR to make hand-held photos even sharper and it gets even better.
And… even better lenses will be needed in the future. The megapixel race has given us incredibly good sensors in terms of definition and dynamic range, and that coupled with sharper lenses has pushed the quality of small format photography so high that I’ll wager that the output quality of small format now matches or exceeds that from the 6x7cm cameras of the film era. And the quality will relentlessly keep getting better and better until the theoretical limits are approached as they have been with current microprocessor technology.
Watch out @Joanna, your big Ebony is going to be even more obsolete before too much longer!
I could argue that both ways against the middle but this is not necessarily the best place.
