I think most of your numbers are correct. There was a different ratio before one of the Hard Forks, regarding payouts, from what I recall. I'm not sure if you factored that in or not.

I'm pretty sure the Hard Fork to temporarily remove liquidity rewards Did go through.

I think the idea is for advertisers to purchase SP and up vote their ads or infomercials or sponsored content or whatever form it may take, to start the ball rolling toward others up voting an expected popular post. I feel like Ned, Dan and company have thought this through a bit, as they do seem to have future plans before we all hear of them. I think this will be an interesting experiment to see what form of advertising works on here, if any.