Sorry for clickbaity title, obviously there will only be 21M BTC.
It is less than 21M bitcoin.
How is the 21 Million Bitcoin Cap Defined and Enforced?Bitcoin controlled supply.It is 20999999.9769
BTC.
But with more banks, institutions, and CEXs trying to custody the BTC and creating ETFs, options, and perhaps other derivatives in the future, how can we be sure there won't be an "infinite" supply of these synthetic "shares" of BTC?
Those shares are not bitcoins and people should not buy such shares because it's not bitcoin, and they don't have private keys or mnemonic seeds.
If investors want bitcoin, they need to buy bitcoin, and avoid shares. They can trust capital management of Bitcoin Spot ETFs but trust sometimes will be punished by scammers.
Nobody is able to change the Bitcoin protocol to have more than 21M bitcoin. It's possible but nobody actually want to have more than 21M bitcoins then price of each bitcoin drops considerably.
Can Bitcoin's Hard Cap of 21 Million Be Changed?