A lot of art masterpieces are considered masterpieces because they're examples from a particular art movement (or artist) that changed or expanded preception or concept on a wide scale. Believe it or not, subjective beauty doesn't necessarialy have anything to do w/why they're considered great.
Impressionism (Monet, Degas, etc.) for instance was considered disgusting in its day. However it expanded the idea of what painting could be by developing the concept or idea of "time" in art in its attempt to capture "ignoble fleeting moments" as opposed to the stoic staged propaganda of neo-classicism. Also Cubism (Picasso, Braque, etc) which many still consider "ugly" was developed to reveal the inherently dishonest idea of 3d representation on a 2d plane, thereby changing the perception of what representation meant.
So in a comparison between great art and great knives it helps to know why masterpieces are widely valued in the first place. Sure beauty may be part of the equation but nice engraving to one person might be gaudi to someone else no matter how well done. With knives, like art, the great masterpieces and hence monetary value may eventually be the ones that made wide scale lasting alterations to our preception and the concept of all knives.
Knives like: -Bill Morans damascus
-Lakes early interframes (or any of his interframes due to his name)
-the 1st Spydercos
-etc
Theres no denying that there are some really well crafted knives w/lots of fancy embellishments and damascus and such, and alot of these transcend their craft to become true art objects but do/did they change the world?
Building or marketing a name helps too.
Picasso was a consumate salesman at selling himself and its often argued that Dali was a much better salesman than artist.
Knifemakers w/similar panache will no doubt have knives that obtain eventual monetary noteriety.