Circulating supply should probably be broken down further. What you've described is the total amount mined so far, but that's different from the amount "circulating," which is definitely smaller. Coins are lost over time, irretrievably. And Satoshi has about 1 million coins that have never been moved and some expect may never be moved. Those aren't part of the circulating supply for any practical purposes.
Those coins that are declared lost aren't lost permanently also. Some people say it's possible to access them again using super computers that may come out in the future. There's also the possibility of "miraculously" finding the private keys or seed phrase.