You are looking at this from the wrong perspective, it seems that you think that just because something costs X to produce then that is its value, but things do not work like that, that is the labor theory of value which is closely related to communist ideas, but this is wrong, just take a look at shitcoins, it takes you a certain amount of money to mine them, however if the development is awful then you will never recover your investment, it does not matter how much money you spent you will never recover it as the coin was not worth it.

So it does not mater how much money was necessary to mine a bitcoin, the value of bitcoin, and anything else by the way, depends on how much people are willing to pay for it.