I believe saddle comfort is due to a combination of minimizing the weight on the saddle and having a saddle shape that provides the largest possible bearing surface.
Long ago when I was a boy, some local farmers still used horses to work their fields. In those days horse drawn farm implements had iron seats yet were comfortable enough to sit on all day, day after day. Having sat on such an iron seat myself while operating a mower, I know how comfortable these seats were. They were comfortable because the shape matched anatomy and they were large enough to spread weight over a large area. This is likely the reason leather saddles, after breaking in over time, can be comfortable.
The situation with a bike is different because comfort is desirable but we have to be able to peddle. Some bike saddles, even though appearing narrow, evidently may fit an individual anatomy so well that body weight is comfortably spread out and are therefore well suited to a particular rider. My guess is that a wider saddle will likely be more comfortable for most people if the nose part of the saddle is a suitable shape.
Everything about saddle fit is difficult or impossible to quantify. It seems that fitness is part of the issue also because as fitness increases, not so surprisingly, more force is put on the peddles and this reduces weight on the saddle as well as on the bars and hands.
One surprising effect is that thick padding is often not comfortable after an hour or so. There are many comments on saddle threads confirming this and it is my experience also. I have found I like a saddle with a cut out center section because it not sensitive to tilt. This may not be true for everyone but I can tilt a cutout saddle through a range of several degrees with equal comfort and as a consequence the drops are comfortable also.
My overall take on this issue is that saddle comfort is a moving target that changes with enough miles in the legs. In my two years of cycling I've purchased about 5-6 saddles and now have a good idea what works for me.