I would refer you to this, for the latter point (Bitcoin 2.0...);
https://steemit.com/steem/@dan/steemit-s-evil-plan-for-cryptocurrency-world-domination
With regards to the former, there would certainly be issues if market cap went below SBD circulation. It is possible, but unlikely IMO. SBD supply will be 2.5% of the value of New Steem Created moving forward though, and is currently (roughly) 1% of Mcap, so we have quiet a bit of room..