Bitcoins price is derived from the cost of compute, energy and a finite supply. These are the fundamentals of bitcoin. Just like the price of gold is set mostly by the cost of machinery, energy and labour to pull it out of the ground and then the extra cost of maintaining or protecting the gold reserves, there’s also a finite supply. Bitcoin going PoS would be a bit like the current gold system saying we’re not going to take it out of the ground any more but instead we’re going to say who ever owns the current stockpile gets an imaginary credit for more gold. Any new gold entering into circulation will only be in the form of gold contracts.