>but the purpose of including a high-quality DSLR shot in the comparison would be as a reference point for "this is the best that the shot can possibly look"
Ever heard of medium format? (and there are other options too).
Commercial medium format cameras are, disappointingly enough, optimized for studio shoots and don't do well in low-light or other challenging conditions. Hasselblad isn't best at everything.
Depends on what one asks from them. They might don't do as well on low light as a Sony high-end mirrorless, but they far exceed what their analogue medium format ancestors did (ISO/noise wise), which is more than enough.
I find this modern preoccupation with crazy ISOs (which one would never use in the film era) a red herring. Especially for landscape work, it's a non issue. What you want there is excellent dynamic range, which those offers.
And there are some such as these that are quite the monster: Pentax 645Z.