it can be and is! I think for the purposes of this discussion it’s just a matter of “are the souls games sufficiently unique in their own right, or is their DNA substantially unique enough from king’s field, i.e. are their other inspirations more significant, that calling it an acceleration of king’s field rather than a slowing down of other genre staples is more useful to our understanding?”
certainly, if you draw a line with multiple points on it, with demon’s souls in the middle and bloodborne at one end, it makes sense to have king’s field at the other end, in terms of how the dungeon crawler design was incorporated and then streamlined (and in acknowledgment of the design documents that from already had on hand). but if you’re looking at dark souls as ur-modern-action-RPG, I’m not as certain.