bitUSD is pegged to USD, a debt-based currency. When USD goes to zero value (see note 3), bitUSD or any USD pegged token will follow by definition, even if it is backed by collaterized currencies that have value (it will take less and less bitshares to support a near zero valued USD). Moreover, future contracts are debt-based economical tools that will easily be replaced by smart contracts in a value-based (blockchain) economy.