[matthewdgreen]

The supply isn't really known. As of this older 2020 article [0], something like half of the total number of (future) Bitcoins haven't moved in at least a year. I've seen figures like 2/3 from later in 2020. Some fraction of those probably represent lost keys, and hence will never move again absent a consensus change. Another fraction represent people who are just sitting on the coins waiting for a chance to sell. But we don't know what the fractions are! These are big uncertainties.

[0] https://www.coindesk.com/10m-bitcoins-havent-moved-in-more-t...

[tromp]

Lost and burned coins are included in the notion of circulating supply, which is simply the sum of all historical block subsidies.