So BTC will continue to be mined until about 2140, when all 21 million are finished. But imagine if there were 21 trillion bitcoins and it finished in say the year 9140, it actually wouldn't make any difference to us than 21 million, because the inflation rate would still be the same. I think the current bitcoin inflation rate is 1.3 percent or whatever. So just imagine if there were 21 trillion bitcoins and 18,648,168 BTC were currently in circulation, do you think people would still say you know there will only ever be 21 trillion bitcoins.... i dont think so. But it would be the same as saying there's only 21 million. Maybe in the year 2130 people can say that when there's only 10 years left but for us who are alive now, why should million or trillion matter. Inflation rate and circulating supply would still be the same.... any thoughts?
The idea of the 21 million limited number of bitcoins is important to keep the system deflationary.
The more bitcoins generated, the higher is the incentive for miners. By 2140 miners won't need incentive anymore, probably because there will be too many transactions and fees will the enough incentive to miners
Changing 21 million to 21 trillion would change the economic balance between transactions/miners/users/deflation model.