This leaves me with a very hypothetical question, what if all btc is burned (or lost)? After all 21m btc has been released, the number can only go down, right? I understand it would take an extreeeemeeely long time, but could humans run out of btc after enough burning? What will continued btc burning do to the economy over time? Is this something that Satoshi Nakamoto considered?
It's impossible for all Bitcoin to be burned or lost because there is no single individual or company that can do that, and if some percentage is burned that increases value rest of the coins.
Bitcoin can always be divided in smaller denominations and used like that, but it's not theoretical at all to say that in future there wouldn't be any new Bitcoin mined, that was intentional.