The rules of Bitcoin is the block rewards halve every about 4 years, thus the inflation halves every about 4 years as well. To end with 21 trillion, and not just 21 million Bitcoin have, the inflation rules would need to be very different from Bitcoin. With the 21 trillion in 9140, you would need some more or less constant inflation for the next 7000 years, but then you would end up with something like fiat, eg not wort hoding because it inflate over time to worthlessness