Respectfully, don't you sell SP delegations and votes yourself as well? If so, by your logic you would be in the equation of this problem too.

Also, I made an open offer to all whale down below. Delegate me some good SP, I will return 60% of curation rewards. No self-votes and SP will be used on posts that add value to the platform. Or you can come up with your own rules and guidelines for curating. If not me, I am sure there are a lot of experienced curators out there that would take this kind of deal. I believe this kind of mechanism would make Steem work for everybody and in a long-term make investors rich. Encouraging adding value to the platform will add significant value to Steem itself, which will mean huge returns on the investment.