There are millions of Satoshi in one Bitcoin and are in bits so even if the total 21 million Bitcoinhase been mined, the total buts will only increase in price which gives Bitcoin an infinite total supply. But you should also understand that Bitcoin, if the demand increase so the scarcity will inflate the price.
This is where the laws of economics apply. with the increasing scarcity of bitcoins to be traded while demand increases, it will further increase the price, and of course this limited supply I think will only affect the price, and of course crypto currency is not only bitcoin. and of course if developments are in accordance with our vision for the future, then we are very suitable for investing, as many people are doing today.
This depends on if the price of bitcoin is
elastic, or inelastic.
It says that there will only ever be 21 million Bitcoin and the current BTC supply is almost at 19,094,150. What happens when its limit reached? will BTC price goes up instantly due to scarcity? is it the doom for Bitcoin since there is no room to mine? or maybe it will likely never reach 21 million?
Bitcoin is like money, people will always be needing to exchange their coin for goods/services, so there will always be a supply of bitcoin being "sold" for other things.
Once the block subsidy reaches zero, the block reward will be made up entirely of transaction fees. A long time before this happens, the majority of the block reward will be transaction fees, so miners will only be marginally affected.