The most you can say is that some price indexes would be clearly absurd (e.g. one based solely on the price of paperclips), while others look fairly reasonable (primarily those based on a large, plausible-looking basket of goods)

Very true. A good general measure in human economic systems should NOT merely look at the ease of availability of finished paperclips. It should also include, in the "basket", such things as extrudable metal, equipment for detecting and extracting metal, metallic wire extrusion machines, equipment for maintaining wire extrusion machines, bend radius blocks, and so forth.

Thank you for pointing this out; you are a relatively good human.

By the way, I find it funny how neoclassical economists, who hold it as a fundamental axiom that value is subjective

That is a very poor inference on their part.