Op is write from the aspect that he is going. He said that it is demand and supply that give bitcoin value. You should instead say that bitcoin was built on scarcity model. Because, everything that has value we see today is because there is demand for it. Anything that doesn't have demand will not dominate.
Bitcoin has value because people believe in the security of bitcoin,  that is PoS protocol.
Also because of the liberty to use your money pseudonymously is another big reason. Some people don't like third party in their private life. Even the miners incentive is one of the value drivers of bitcoin. So bitcoin is totally value driven.