You are but you are wrong. You have to think about all the uses; actual and fictional that both metals have not just industrial use. Gold for instance is seen as money and the best store of value by a lot of people around the world where as arguably platinum isn't and now you need to figure out how that weighs in on the demand for either.
I don't know precisely, no one does as Etlase2 pointed it out, but there are theories that you can speculate on based off of their utility and properties.
It's not. You just lack the complete information about their utilities and properties as most everyone does and then your conclusions based on an incomplete picture don't match up with reality as they shouldn't.