It is the supply and demand. Bitcoin won't hit even $1 if there's no demand for it before but as time passes, price is increasing and thanks to the people who are adopting it and embracing it as investment, currency or medium of exchange.
That made the demand higher so the price reacts accordingly. There's the market capitalization and divide it on how many supply in the circulation now and that calculates the price of bitcoin.
supplies and demand that make the price of bitcoin soar, it takes time until now bitcoin has entered in a decade. great, no, without physicality but can be a valuable asset. I think you should look for other references so you can understand and understand the history of bitcoin.