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.