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Technically, steem pegging system could do that.
It would be less practical than 1 SBD = 1 USD, but so much more stable. Has this come to the witnesses discussion?

Steem would remain liquid but volatile, SBD also liquid but stable. Caters to both sides of the risk aversion scale.

That's what I think. Then just find a few options to author rewards that stay fair compared to authors gains today, and that allow you to choose between volatility and stability