Also - APY from leo.voter currently is 8.31% https://hivestats.io/@leo.voter

As there is 0 inflation and the funds are purchased on open market , the return for delegators can only be self sustainable if it is below 8.31% (curation rewards - any fee or slipperage).

Therefore if returns for delegation would be 16% - while curation rewards are 8.31% that would mean someone is sponsoring (and it would not be sustainable)