if we want to have a stable SBD-USD parity, some active intervention from human is definitely required... as described in my last post: Do Your Part to Restore the SteemDollar Parity.
To restore SBD back to parity, we need the Witnesses to raise the interest rate of SBD, and/or to quote the STEEM/SBD conversion-ratio with a lower rate that would pay more STEEM to the holder as compared to market price.
The fate of SBD will remain the same like now, as long as our "monetary policy makers" are unwilling to take any "open market operations".
As observed, currently most witnesses still quoting their price-feed that only mimic external STEEM/USD prices. At the time of writing, only one witness 
RE: SBD isn't broke: How SBD works on STEEMit