You are greatly overstating the magnitude of the costs. The highest the debt ratio ever got was 9% which means assuming that SBD had no original cost and was all redemeed at that moment (in fact neither was the case), the result would be an incremental 9% dilution.
In fact the cost of debt problems, overstated though they are, was only even that large because action was not taken to properly manage debt earlier into the decline, when the cost would have been extremely modest (e.g. 2% reduced to 1%). Even that is not really a pure cost, except in hindsight. When the STEEM price goes up, the opposite benefit occurs. Given balanced up and down fluctuations, there is no (or negligible) net cost.