As always a great look at things.
I believe SMTs will serve to bring in the users. The question is can Steemit Inc handle the sign ups. It will only take a few decent sized sites to hit your numbers.
The number of sites with 10M monthly active users means that even the smallest percentage using SMTs will be a huge net gain.
RE: How much new money is required now to keep Steem’s price at 12 cents.