> Getting 1 of the 21 million bitcoins is like decentralized proof of saying "I had 48k worth of value in Feb 2021!"
Bitcoin doesn't prove anything about your USD value. Bitcoin blockchain only proves how many Bitcoin you have. Nothing about how much they're worth.
No one cares how much your 1BTC was valued at an arbitrary date in the past. The only thing that matters is how much someone else is willing to pay for it right now.
If you buy 1BTC for $48K, you don't have $48K. You have $0 and 1BTC. Someone else has your $48K.
> It locks in the value that you created forever. Otherwise governments will just keep printing money, and your value gets diluted arbitrarily.
What is inflation? Inflation is when the price of something is pushed up. You don't need to buy Bitcoin to avoid inflation. You can also buy stocks, or real estate, or gold, or businesses, or any other number of investments. Basically, do anything other than put cash under your mattress and you'll avoid currency inflation. Bitcoin isn't even close to unique in this regard. People have been investing to avoid inflation for centuries before Bitcoin came along. This idea that Bitcoin is the only way to avoid USD inflation is a deliberately misleading narrative from the people who want you to buy Bitcoin instead of other assets. Fear-mongering.
Bitcoin, however, is inflating in US dollar terms. It is inflating due to demand-pull inflation, by the textbook definition of inflation. The fixed supply of Bitcoin isn't what drives the price up. The only thing that drives the price up is demand.
> Assuming the mechanisms of protection for the blockchain holds, it should work out exactly as that.
No, blockchain has no notion of price. USD prices of BTC are purely a function of exchanges. Exchanges don't even touch the blockchain until you withdraw from the exchange.
Blockchain only protects your 1BTC. It doesn't protect your $48K value. The $48K value comes from other people buying Bitcoin. Why are they buying Bitcoin? Because they expect the price to go up. Why do they expect the price to go up? Because other people are buying Bitcoin.