There is definitely a point of diminishing returns, but that is subjective as well. For materials, you can probably establish a rough range if you categorize by the scale of the manufacturing of the knife, but you still end up omitting things like form and appearance that are not feasibly separatable from the value of a knife. Example: A Spyderco Domino, a Kizer Megatherium, and a ZT 0450 may have nearly identical materials, but they are vastly different knives that fill different niches. You can’t make a direct value comparison because they have different applications and markets. The role that a knife fills is an intrinsic subjective value that cannot be ignored when trying to make a useful value judgement.