... there will never be enough STEEM for many accounts. in 15 years from now and based on the current code which could change, there will only be double the STEEM in the supply and, there will only be around 6 million more added each year through inflation. That is not enough for a hundred million accounts as each account could only have a max of 6 STEEM.

Source : https://steemit.com/steem/@tarazkp/social-steem-capital-and-transactions-of-relationship