Currently Proof of Work is deemed by the market to be valuable, by definition, so it is merely speculation that the market is over-valuing cryptocurrency that y

Currently Proof of Work is deemed by the market to be valuable, by definition, so it is merely speculation that the market is over-valuing cryptocurrency that your claim that PoW is not valuable is based on. Anyway, I would agree that if the PoW had a secondary purpose, like enhancing the efficiency of the blockchain, or providing scientific compututation, it would provide more value to humanity.