It has nothing to do with the fixed number. It's like stocks. Think shares. They divide in number as their value increases. They start out as an Initial Public Offering--people can purchase them for what they will.

When people from the outside have the opportunity to purchase steem tokens for their businesses, this will revolutionize the world's economy as larger corporations incorporate crypto currency into their model without even realizing it. They'll do Initial Coin Offerings, and bam. Steem value increases (as does the reward pool).

I posted an article on it awhile ago, that I think may answer some of the economical questions on how it impacts the growth here, if you'd like to read it: Smart Media Tokens Take Over the World

You'll have OUTSIDERS speculating on tokens that are steem tied. It's brilliant. I can't friggin wait.