The algorithm of bitcoin is set to be limited so when all bitcoin has been mined, the miners will no longer be able to receive block rewards because there are no more coins to be generated. But why this?
The total supply is fix at the day the Genesis block is mined by Satoshi. No one can change the total supply of Bitcoin.
Bitcoin source code is opened so everyone can use it to make their forked or clone altcoins. And they can change total supply and premined coins if they want. They are not bitcoin, never, they are only shit altcoins and never get attention and value of bitcoin.
I don't see how bitcoin community need more bitcoin in total supply. The scarcity of bitcoin helps it has a high price, now and higher in the future. Higher total supply means lower price. We don't need such total supply that has bad effects on price.
If you are in crypto long enough, you will see some shit altcoins have burn events. They do that to reduce total supply as their attempts to help their coins have higher price. They don't lose anything, those burnt coins are from premined, from the air so at the event day, they burnt them into the air again.