What do you think will happen July 4th and the following week?
I won't quote you on it! (:
I would assume that some would cash out their SBD into STEEM and then sell the STEEM for BTC essentially exiting the system.
This would cause the price to drop.
Some people would see this as a buying opportunity to "buy influence" for cheap, which would cause the price to raise again and stabilize somewhere.
Those people would only be interested in "buying influence" on steem(it) if the platform and network are in fact attracting quality users with quality content, which can attract eyeballs and attention (what drives most current websites).
So I guess it all boils down to the product itself. If it works (good content, good curation, good engagement) then the underlying STEEM will hold some value.