For me, the reason why Bitcoin became king is because he is always at the top, and when he is said to be like a king, he is always followed by those who are below him in terms of price value.
Because it has been witnessed by other communities here in the past few halvings, when the value of Bitcoin increases, most potential cryptocurrencies also follow its rise, and if the value of Bitcoin falls, most or all other cryptocurrencies also follow the fall in the price value they have.
Bitcoin is said to be king because it is decentralized in nature.
2. It has limited supply which is 21m
3. It is used for payment without a third party across boarders.
4. Bitcoin stands as an hedge to inflation.
5.Bitcoin is also use as a store of value and an asset.
6. All altcoins depends on bitcoin price movement.
7. The halving event.
Without making a comprehensive long post about why bitcoin is king of all cryptocurrency, you have simply summarized some of it's outstanding attributes. Bitcoin is the first crypto and it introduced decentralized digital currency into the financial system, it has no boundaries. Unlike fiat, that the printing of it's currency has no limit, bitcoin from creation has already been given a limited supply, very unique. The bitcoin p2p transaction is the first of it's kind, that does not require any centralized influence, except by choice of using exchanges. Many investors in bitcoin, have become richer, because of it's potentials, as a business currency.
Bitcoin is a pacesetter for altcoins, it stands on it's own as "the king" of them all. Altcoins follows it's patterns to have relevance in the crypto market.