The standard for owning Bitcoin is by having a wallet (ideally a non-custodial wallet), which contains: a private key that gives full control of the coins, and also a public address (wallet address) that allows individuals to receive and verify transactions on the Blockchain.
A Bitcoin wallet usually contains a lot of private keys, from which associated public keys and public addresses are derived by known cryptographic recipies. But yes, normally you need to have the private key to move coins in the blockchain. The blockchain itself doesn't know or use public addresses, those are only recipies for how to construct so-called unlock scripts for coins.
As designed in the Bitcoin protocol, there can be only 21 million BTC in circulation, even though other enthusiasts might think otherwise due to proven calculations and reasons not to estimate.
By design there can be only 20,999,999.9769
BTC, of which some are provably lost or unspendable (as already said e.g. the Genesis block coinbase subsidy of 50
BTC is unspendable, even if you had the private key; there are few examples of miners who didn't claim the total allowed block subsidy and transaction fees, those unclaimed coins are forever lost, too; any coins sent to OP_RETURN outputs are burned and lost; ...).
Dormant wallets, also known as hibernated wallets, are considered to house lost Bitcoins. Identifying the total number of lost bitcoins can be very challenging or even impossible due to the fact that there are several inactive wallets connected to the Blockchain, making it impossible to tell who is holding and who has lost.
Why those should be considered lost coins? Elaborate, please!
There might be a likelyhood that early coins are lost coins because wallets were deleted when Bitcoin didn't yet had a accepted value. But we can't know if those are really lost.
For example, Satoshi Nakamoto happens to mine the first block. The Genesis address created holds about 99.85 BTC and is currently a dormant wallet. There are also speculations that Satoshi might have thousands of dormant wallets as they were used to receive block rewards. By subtracting the amount of Lost Bitcoin from 21 million, it is likely that we are left with an amount lesser than the total supply when unlocked.
With 100% certainty blocks 0 (Genesis) and block 9 can be attributed to Satoshi Nakamoto (Satoshi sent some coins from coinbase of block 9 to Hal Finney and this is well documented).
See
http://satoshiblocks.info/, there's some scientific evidence that Satoshi mined around 21954ish blocks (this yields ~1.1million
BTC). Every of those coinbase outputs were mined to a public key, never to a public address!
This
bitcoinexplorer.org lists blocks with a miner attribution.
There are hundreds, if not thousands, of dormant wallets that house Bitcoin of different amounts. When we calculate all together, we realize that we are short of the total supply, which I think would trigger scarcity as more people would want to hold the ones available.
Why are you so concerned about dormant wallets exactly? We can't really calculate them all together, except maybe that you could put them into buckets of unspent age. But that doesn't give you any certainty if those are only dormant or provably lost. What's the fuss about them anyway?
I added my answers in
color.
Discussion Questions- Do you think all dormant wallet (long inactive wallets) are gone forever?
No, but some may be. We can't know. - As we are not certain of Satoshi's return, should we be bothered about his dormant wallets?
Not at all. - do you think lost Bitcoin can cause Bitcoin scarcity in the future?
Provably lost ones, yes. But Bitcoin is already of finite scarcity, who cares if more or less? - From a total of 21million total supply, can you attempt a prediction guess of the total number of Bitcoin that would be in active wallets after all Bitcoin has been mined?
No, likely impossible. The only certainty is: the pile of lost coins only grows, never shrinks.