Without negative interest rates on SBD, there is no incentive to hold Steem but instead SBD. But SBD grows endlessly and in the process increases the steem supply to back its peg.
I don't think SBD should be abolished, but it needs to be reined in and the simplest way is to allow interest to be charged on it rather than paid. Too many people are holding SBD but it's not people's fault entirely because the supply never stops growing in proportion to Steem. This is the problem. It has to be kept at a lower proportion compared to Steem or Steem can never rise in price.