Correct, the highest voting return is to sell your vote because you get the curation value of the vote + money on top of it. Self voting isn't as good, which is why some of the most flagrant self voters moved over to bidbots and got a better return there.
I don't think changing curation rules or amounts will change much. The only real option is community led downvotes of socially and arbitrarily deemed undesirable content.
RE: Why I Advise Against Linear Reward