I think cryptocurrency is very difficult and seems very unsuitable to replace the regular currency, better cryptocurrency remains in use as an alternative currency only but if you want to replace the ragular currency then the total supply of the coin must be very much and have a very good developer.
Why would you need to increase the total supply of a coin to accommodate everyone, take the case of bitcoin, it has 21 million coins and it can be divisible to eight decimal places and so we do not need more coins and there will satoshi left for everyone to transact.