You're absolutely right, one could optimize with respect to any of the infinite attributes a thing has. We could have optimized for the shininess of the doses,

You're absolutely right, one could optimize with respect to any of the infinite attributes a thing has. We could have optimized for the shininess of the doses, or how good they smelled, and those would be ridiculously irrelevant properties to optimize for. The question is how relevant the use of which resources as a metric in comparison to people not getting sick? Does it even take more resources to distribute a 10x dose vaccine vs x? Is the production of the active ingredient a linear contributor to the overall cost function, which probably is dominated by a lot of the constant costs? We're not talking about 250mg vs 500mg tylenol after all.