Not only you don't understand the basic principles of Bitcoin, you are also misinformed about the fiat system. Money as we know it, dollar, euro, etc, is infinite. The fed prints trillions just by pressing a button and will keep doing so forever because without this tons of liquidity the system would collapse. All this money is constantly looking for investments that provide yield and Bitcoin happens to be just that, the best performing asset in the past 5, 10 and 15 years. Nothing comes even close, not real estate, not the stock market, and not even Nvidia.
Besides, there are $900 trillion of global wealth, BTC is just 1.2 T, the room for growth is huge. Blackrock, fidelity and many others have already invested billions in BTC, do you think they are wrong?