My theory is that once the sharpness is taken off the ridges of even very bad machine marks, on chisels or plane soles, then friction will be very low and further polishing would achieve nothing. The first few face down taking off the burr operations will do this, or just usage.
I found this out by chance when I bought a new plane. QS no 4 I think. The sole was ground coarsely enough to see the machine marks, which were straight along the sole. At first for a week or so it tended to track in a straight line. Before I got around to polishing, the tracking had stopped as the sharpness of the scratches had been taken off by use. You could still see them, but no need to do anything!
Chisels and plane blades need to be shiny close to the edge as that's where all the pressure and friction is, but further back doesn't matter.
Also the concern about flattening/polishing only seems to feature with the new boys (particularly R Cosman!) and doesn't get a mention in the older books.
Older chisels and plane blades are usually laminated on one side, with harder steel. This is a reason for keeping the cutting edge on that side too i.e. keeping the laminated face fairly flat.