Last I checked the median payout was .01 SBD. SPS will lower that reward for producing content. It's retarded to further decrease incentive to become and stay a Steem user. Retention was already at ~7.5% YOY last I checked. Reducing potential rewards will not improve retention, and will shrink the market for Steem. You might note that reducing the market depresses the price.

This tax will create capital losses, not capital gains, making an existential problem worse.