Well one idea that has been floated recently, which I am very much on board with, is that at some point if and when SMTs become the main focus for consumers then the "proof of brain" distribution will be removed from the STEEM token, so STEEM will only be used for Resource Credits (much like how TRX or ETH are used today). In that case the inflation would be reduced by around 65%.

So with some quick math, the inflation drops to around 25k STEEM / day from the 75k you quoted, which would only take about 250 new 100 SP users / day to absorb. That should be a piece of cake assuming we have some actual popular applications on here.